Celenza v Celenza Executor for Estate of Maria Celenza [No 2] - [2025] WASC 277

JURISDICTION : SUPREME COURT OF WESTERN AUSTRALIA
IN CHAMBERS

CITATION:   CELENZA -v- CELENZA EXECUTOR FOR ESTATE OF MARIA CELENZA [No 2] [2025] WASC 277
CORAM:   STRK J
HEARD:   ON THE PAPERS
DELIVERED          :   10 JUNE 2025
PUBLISHED           :   9 JULY 2025
FILE NO/S:   CIV 1528 of 2022
BETWEEN:   PAIGE SARAH MARIA CELENZA
Plaintiff
AND
NICOLA CELENZA EXECUTOR FOR ESTATE OF MARIA CELENZA
Defendant
NICOLA CELENZA EXECUTOR FOR ESTATE OF MARIA CELENZA
Plaintiff by counterclaim
PAIGE SARAH MARIA CELENZA
First Defendant by counterclaim
THE OFFICIAL TRUSTEE IN BANKRUPTCY on behalf of MARCO CELENZA
Second Defendant by counterclaim
MARCO CELENZA
Third Defendant by counterclaim
OSVALDO CELENZA
Fourth Defendant by counterclaim
MAURO CELENZA
Fifth Defendant by counterclaim
EZIO CELENZA
Sixth Defendant by counterclaim
NICOLA CELENZA
Seventh Defendant by counterclaim

Catchwords:

Practice and procedure - Application for leave to file a supplementary expert report - Turns on own facts

Legislation:

Rules of the Supreme Court 1971 (WA) O 1 r 4A, r 4B

Result:

Application granted

Category: B

Representation:

Counsel:

Plaintiff	:	SK Shepherd
Defendant	:	PR MacMillan
Plaintiff by counterclaim	:	PR MacMillan
First Defendant by counterclaim	:	SK Shepherd
Second Defendant by counterclaim	:	No appearance
Third Defendant by counterclaim	:	No appearance
Fourth Defendant by counterclaim	:	No appearance
Fifth Defendant by counterclaim	:	No appearance
Sixth Defendant by counterclaim	:	No appearance
Seventh Defendant by counterclaim	:	No appearance

Solicitors:

Plaintiff	:	Murray Chambers
Defendant	:	Peel Legal Barristers & Solicitors
Plaintiff by counterclaim	:	Peel Legal Barristers & Solicitors
First Defendant by counterclaim	:	Murray Chambers
Second Defendant by counterclaim	:	No appearance
Third Defendant by counterclaim	:	No appearance
Fourth Defendant by counterclaim	:	No appearance
Fifth Defendant by counterclaim	:	No appearance
Sixth Defendant by counterclaim	:	No appearance
Seventh Defendant by counterclaim	:	No appearance

Case(s) referred to in decision(s):

Anderson v Minister for Infrastructure Planning & Natural Resources [2006] NSWLEC 725; (2006) 151 LGERA 229
AON Risk Services Australia Ltd v Australian National University [2009] HCA 27; (2009) 239 CLR 175
Attorney-General of Botswana v Aussie Diamond Products Pty Ltd [2009] WASC 301
Attorney-General of Botswana v Aussie Diamond Products Pty Ltd [No 2] [2012] WASCA 73
Clough & Rogers v Frog (1974) 48 ALJR 481
Cropper v Smith (1884) 26 Ch D 700
Emeco International Pty Ltd v O'Shea [2012] WASC 282
Hamersley Iron Pty Ltd v James [2015] WASC 10
Harrington-Smith v Western Australia (No 7) (2003) 130 FCR 424
Harrington-Smith v Western Australia (No 9) [2007] FCA 31; (2007) 238 ALR 1
Landel Pty Ltd v Insurance Australia Ltd [2021] QSC 247
Life Combat Sports Pty Ltd v The World Institute of Martial Arts [2025] WASC 21
McKay v Commissioner of Main Roads [No 6] [2010] WASC 274
McMurray v AIG Australia Insurance Ltd [No 4] [2020] WASC 210
Moore v Landsdale Pty Ltd [2012] WASC 452
Orrong Strategies Pty Ltd v Village Roadshow Ltd (2007) 207 FLR 245
Queensland v JL Holdings Pty Ltd (1997) 189 CLR 146
Sali v SPC Ltd (1993) 67 ALJR 841
Seeley International Pty Ltd v Jeffrey [2013] VSCA 288
Treneer v City of Stirling [2002] WASCA 281
Warner‑Lambert Company LLC v Apotex Pty Ltd [2014] FCAFC 59; (2014) 311 ALR 632

STRK J:

(This judgment was delivered extemporaneously on 10 June 2025 and has been edited to correct infelicities of language, and to include headings, complete references and citations.)

Introduction

By a letter filed on 13 May 2025, the defendant/plaintiff by counterclaim applied for leave to file a supplementary expert report of Dr Roger Clarnette. The application was opposed by the plaintiff/first defendant by counterclaim. All other defendants to the counterclaim have either filed or communicated to the court their intention not to take part in the proceeding and to otherwise abide by the court's decision.
The plaintiff/first defendant by counterclaim and the defendant/plaintiff by counterclaim agreed that the application for leave ought be determined on the papers filed. After considering the same, I have determined that it is appropriate that leave be granted. These are my reasons.

Materials before the court

I first describe the materials before the court.
In support of the application, counsel for the defendant/plaintiff by counterclaim read three affidavits.

Affidavit of Jamie William Sloan sworn 12 May 2025

The application was supported by the affidavit of Jamie William Sloan sworn on 12 May 2025. Mr Sloan is a solicitor employed by Peel Legal Barristers and Solicitors, the solicitors for the defendant/plaintiff by counterclaim. Mr Sloan attached to his affidavit documents marked JS1 and JS2.
In his affidavit Mr Sloan deposed to a letter having being sent to Stuart Shepherd (the legal representative of the plaintiff/first defendant by counterclaim), on 7 May 2025 concerning Dr Clarnette's expert evidence.[1] That letter was written by Matthew Bassett‑Scarfe (the managing legal director of Peel Legal Barristers and Solicitors), and that letter enclosed a copy of the draft further expert report of Dr Clarnette along with three letters from Peel Legal to Dr Clarnette dated 1 April 2025, 4 April 2025 and 5 May 2025. In the letter dated 7 May 2025 Mr Bassett‑Scarfe recorded that the only further amendments to Dr Clarnette's draft report would be to accommodate the issues in the 5 May 2025 letter addressed to Dr Clarnette (that is, to annex to the final further expert report the correspondence from Peel Legal to Dr Clarnette, and a statement to the effect that Dr Clarnette had read the Harmonised Expert Witness Code of Conduct found in the Supreme Court of Western Australia's Consolidated Practice Directions at PD 4.5.2.1, and agreed to be bound by the same).[2]
[1] Affidavit of JW Sloan sworn 12 May 2025 par 3, JS1.
[2] Affidavit of JW Sloan sworn 12 May 2025, JS1 (page 7).
In his affidavit Mr Sloan also described the correspondence sent to Mr Shepherd on 9 May 2025. This correspondence was a letter from Mr Bassett‑Scarfe to Mr Shepherd in which among other things, Mr Bassett‑Scarfe noted that the amendments to the report of Dr Clarnette were not substantial, and that the new materials on instructions (excluding the expert affidavit already filed) were not substantial.[3]

Affidavit of service of Mr Sloan sworn 14 May 2025

[3] Affidavit of JW Sloan sworn 12 May 2025, JS2 (page 28).

The application was also supported by an affidavit of service of Mr Sloan sworn on 14 May 2025, to which Mr Sloan attached documents marked JS1 and JS2.
In his second affidavit, Mr Sloan deposed that on 13 May 2025 he served the plaintiff/first defendant by counterclaim, the second defendant by counterclaim, the third defendant by counterclaim and the seventh defendant by counterclaim by email with a copy of the application made by letter for leave to file a further expert witness report dated 13 May 2025; a memorandum pursuant to O 59 r 9(2) of the Rules of the Supreme Court 1971 (WA) filed 13 May 2025; the affidavit of Mr Sloan sworn 12 May 2025; and the affidavit of service of Mr Sloan sworn 13 May 2025.[4]
[4] Affidavit of service of JW Sloan sworn 14 May 2025 pars 3 - 5, JS1.
In his affidavit of service Mr Sloan deposed that on 14 May 2025 he also served by email on the same parties a copy of a minute of proposed orders filed on 14 May 2025; and a memorandum pursuant to O 59 r 9(2) of the Rules of the Supreme Court filed on 14 May 2025.[5]

Affidavit of Mr Sloan sworn 3 June 2025

[5] Affidavit of service of JW Sloan sworn 14 May 2025 pars 6 - 8, JS2.

The application was also supported by a further affidavit of Mr Sloan sworn on 3 June 2025, to which Mr Sloan attached a document marked JS1.
In his third affidavit Mr Sloan deposed that the attached document was a true and correct copy of a further supplementary expert report prepared by Dr Clarnette dated 1 June 2025.[6]

Submissions

[6] Affidavit of JW Sloan sworn 3 June 2025 par 3, JS1.

The application for leave was also supported by a written outline of submissions filed on behalf of the defendant/plaintiff by counterclaim on 20 May 2025.

Materials in opposition

No affidavit was read in opposition to the application. Counsel for the plaintiff/first defendant by counterclaim filed in opposition to the application a written outline of submissions on 26 May 2025 and a supplementary outline of submissions on 6 June 2025. Both outlines were filed out of time. Leave was sought and obtained on 10 June 2025 to extend the time for the plaintiff/first defendant by counterclaim to comply with the court's orders as to the filing of supplementary submissions. The submissions filed on behalf of the plaintiff/first defendant by counterclaim in opposition to the application were considered and weighed in determining the application.

Background

The procedural history to the application is long and unfortunately, complicated. It is necessary to provide an overview of the background to the application, particularly so that the need for leave and the objection to leave being granted may be understood in context.
By an order made on 10 October 2023, the parties were granted leave to adduce expert evidence at trial as to the capacity of Maria Celenza in executing the probated will.[7] It was also ordered that by 7 November 2023 the plaintiff by counterclaim provide to the defendant by counterclaim a copy of the report or the substance of the evidence of any expert witness whose evidence was to be adduced by the plaintiff by counterclaim; and the defendant by counterclaim was by 21 November 2023 to provide the plaintiff by counterclaim with a copy of the report or the substance of the evidence of any expert witness whose evidence was to be adduced by the defendant by counterclaim.[8] The time for compliance with respect to that order was extended on 12 December 2023.[9]
[7] Order 5 of the orders made by Registrar Fatharly on 10 October 2023.
[8] Orders 6 and 7 of the orders made by Registrar Fatharly on 10 October 2023.
[9] Orders 1 and 2 of the orders made by Registrar Fatharly on 12 December 2023.
A copy of the report of Dr Clarnette was filed under cover of a letter from Peel Legal on 7 March 2024. The affidavit of Dr Clarnette was filed on 11 April 2024, to which Dr Clarnette attached a copy of his expert report; a copy of correspondence as between Dr Clarnette and Peel Legal from 28 August 2023 to 29 August 2023; a copy of correspondence as between Dr Clarnette and Peel Legal from 22 September 2023 and 27 September 2023; a copy of correspondence as between Dr Clarnette and Peel Legal dated 27 September 2023; and a copy of correspondence received by Dr Clarnette from Peel Legal dated 18 August 2023.
The first defendant by counterclaim elected not to file any expert evidence as to the capacity of Maria Celenza in executing the probated will.

The evidence of Dr Clarnette

At trial, the defendant/plaintiff by counterclaim called Dr Clarnette. His affidavit of 11 April 2024 (to which Dr Clarnette's report and instructions were attached) was tendered.[10] Also tendered was Dr Clarnette's curriculum vitae which had been filed on 25 March 2025 under cover of a letter from Peel Legal.[11]
[10] Exhibit D6; ruling as to admissibility, see ts 278 - 281 (27 March 2025).
[11] Exhibit D5.
The plaintiff/first defendant by counterclaim had objected to the tender of Dr Clarnette's report on various grounds. While Dr Clarnette's report was admitted into evidence, counsel for the plaintiff/first defendant by counterclaim raised (and in my ruling I noted) that the report contained several issues which may ultimately affect the weight given to the opinions there expressed.[12]
[12] ts 278 - 281 (27 March 2025).
The trial time set aside for Dr Clarnette's evidence on 27 March 2025 was subsumed by the hearing of the objection to the tender of his report. His cross‑examination has not commenced.
In the course of the trial and after Dr Clarnette's report was tendered, counsel for the defendant/plaintiff by counterclaim foreshadowed the possibility of making this application.[13]
[13] ts 287 (27 March 2025).
On 2 April 2025 a letter was filed on behalf of the defendant/plaintiff by counterclaim which recorded that Mr Bassett‑Scarfe had written to Dr Clarnette seeking a further supplementary report to assist in clarifying the report Dr Clarnette had already provided.[14]
[14] Letter from Peel Legal Barristers and Solicitors to the Associate to the Honourable Justice Strk filed 2 April 2025 (Folio 138 of the court's record).
At a directions hearing on 7 May 2025 counsel for the defendant/plaintiff by counterclaim raised again the intention to seek leave to rely upon a supplementary report of Dr Clarnette. During that hearing it was acknowledged by counsel for the defendant/plaintiff by counterclaim that an application for leave to adduce further expert evidence would need to be made, supported by an affidavit which explained the delay.[15] I understood that by reason of him being away, Dr Clarnette's supplementary report could not be finalised until his return, but that an application for leave would be filed in any event on the basis of an advanced draft of Dr Clarnette's proposed supplementary report.[16]

Correspondence surrounding application

[15] ts 394 - 397 (7 May 2025).

[16] ts 394 (7 May 2025).

Upon receipt of a draft supplementary expert report of Dr Clarnette on 20 April 2025, Peel Legal on behalf of the defendant/plaintiff by counterclaim wrote to Dr Clarnette on 5 May 2025 requesting that Dr Clarnette include a number of matters in his draft supplementary report before finalising it. Peel Legal requested Dr Clarnette include:[17]
(a)an acknowledgement that Dr Clarnette had read the Harmonised Expert Witness Code of Conduct and agreed to be bound by the same;
(b)a copy of Peel Legal's letters dated 31 March 2025, 4 April 2025 and 5 May 2025 as annexures to his report; and
(c)if clear from the deceased's medical records, the identity of any medical practitioner that performed the tests or examinations of the deceased referred to by Dr Clarnette in his report.
[17] Affidavit of JW Sloan sworn 12 May 2025, JS2 (page 19).
On 7 May 2025 (following the directions hearing before the court on that date) counsel for the plaintiff/first defendant by counterclaim was sent a copy of the draft supplementary expert report of Dr Clarnette dated 20 April 2025 and the letters of instruction sent to Dr Clarnette on 1 April 2025, 4 April 2025 and 5 May 2025. By that correspondence Mr Shepherd was informed that the only further change to Dr Clarnette's proposed supplementary report would be:[18]
to accommodate the issues raised in our letter dated 5 May 2025 as enclosed. These substantially are to annex our abovementioned letter, as well as a statement that Dr Clarnette has read the Harmonised Expert Witness Code of Conduct and agrees to be bound by the same.
[18] Affidavit of JW Sloan sworn 12 May 2025, JS1 (page 7).
The 20 April 2025 draft supplementary expert report did vary from the report of Dr Clarnette which was attached his affidavit of 11 April 2024 and tendered at trial.[19] The substantive changes were that:
(a)reliance on the lay evidence of Ezio Celenza and Osvaldo Celenza was omitted; and
(b)the draft included further explanation as to how Dr Clarnette had reached his opinion as to the capacity of the deceased on 23 February 2016.
[19] Exhibit D6.
As to the 20 April 2025 draft, there appeared to be no change to the conclusion reached and opinion expressed by Dr Clarnette that '[i]t is more likely than not that the deceased lacked the capacity to properly execute a will on 23 February 2016.'[20]
[20] Exhibit D6 (page 8); affidavit of JW Sloan sworn 12 May 2025, JS1 (page 10).
On 29 May 2025 the court received an email communication from Mr Bassett‑Scarfe (copied to the other parties to this proceeding) attaching the proposed supplementary report of Dr Clarnette dated 28 May 2025 and a letter from Peel Legal to Dr Clarnette dated 23 May 2025. It was noted in that email that:
the only outstanding issue with the report is as to whether the inclusion of the materials related to the correspondence 23 May 2025 enclosed at the front of the report, which the expert has not referred to. That simply concerned queries from the expert as to the level of compliance required by the Code to identify medical practitioners from the medical notes arising from PD 4.5.2.1 paragraph 3(g).

Status of the trial

The application for leave was made in circumstances where the trial of the claim and counterclaim had commenced on 26 March 2025, had continued on 27 March 2025, and had again continued for a half day on 7 April 2025. It was necessary to adjourn the trial part heard.
The court was informed in the course of the trial that Mr Shepherd was leaving the jurisdiction for vacation on 13 April 2025.[21] The court was later informed that he would return chambers on 5 May 2025.[22] The trial was adjourned part heard, and following a hearing on 7 May 2025, by orders made on the same day the court allocated a further two days for trial, 13 June 2025 and 3 July 2025 (which orders took into account counsels' limited availability).

Conferral as to the application

[21] ts 341 (27 March 2025).

[22] Affidavit of JW Sloan sworn 14 May 2025, JS1.

Order 59 r 9(1) of the Rules of the Supreme Court provides that no order shall be made on an application in chambers unless the application was filed with a memorandum stating that the parties have conferred to try to resolve the mattes giving rise the application; and the matters remain in issue between the parties. Subrule (2) affords the court the discretion to waive the operation of subrule (1) in a case of urgency or other good reason.
In the memorandum filed with the application, waiver was sought on behalf of the defendant/plaintiff by counterclaim on the basis that:[23]
(a)the solicitors for the defendant/plaintiff by counterclaim had sent correspondence to Mr Shepherd, counsel for the plaintiff/first defendant by counterclaim, on two occasions on 7 May 2025 and inviting conferral in person or by telephone on 8 or 9 May 2025;
(b)no response was received from Mr Shepherd to the invitation to confer; and
(c)the solicitors for the defendant/plaintiff by counterclaim had on 9 May 2025 sent further correspondence to Mr Shepherd, by which letter Mr Shepherd was put on notice of the intention to file the application and intention to seek waiver of the obligation to confer.
[23] A signed memorandum filed on 14 May 2025 was relied upon in substitution for the unsigned memorandum filed on 13 May 2025.
In the minute of proposed orders filed on behalf of the defendant/plaintiff by counterclaim on 14 May 2025, the form of orders pressed were as follows:
1. The Defendant/Plaintiff by Counterclaim have leave to rely on a supplementary report from Dr Clarnette dated 20 April 2025 as amended to comply with the requirements of the Harmonised Expert Witness Code of Conduct.
2. The costs of the application be in the cause.
The application, a copy of the memorandum seeking waiver under O 59 r 9(2) of the Rules of the Supreme Court, and two supporting affidavits were served on Mr Shepherd on behalf of the plaintiff/first defendant by counterclaim on 13 May 2025. A copy of the minute of proposed orders and a substituted memorandum seeking waiver under O 59 r 9(2) of the Rules of the Supreme Court were served on 14 May 2025.[24]
[24] Affidavit of service of JW Sloan sworn 14 May 2025.
Programming orders were made on 15 May 2025 for the filing of an outline of submissions in support of the application, and the filing of any affidavits and an outline of submissions in opposition to the application. The application for leave was otherwise then listed for hearing on 29 May 2025.

Submissions in opposition

In accordance with the programming orders made on 15 May 2025, the plaintiff/first defendant by counterclaim was ordered to file any affidavits and an outline of submissions in opposition to the application by 4.00 pm on 22 May 2025. At the hearing on 15 May 2025 Mr Shepherd made no objection to the time for compliance.[25]
[25] ts 484 (15 May 2025).
On behalf of the plaintiff/first defendant by counterclaim, Mr Shepherd filed an outline of submissions on 26 May 2025. The submissions were out of time, and no application was made prior to the hearing on 29 May 2025 to vary the time for compliance with the orders made on 15 May 2025.

Hearing on 29 May 2025

At the hearing on 29 May 2025 counsel for the defendant/plaintiff by counterclaim pressed that the application should be granted, primarily because no prejudice would be suffered by the plaintiff/first defendant by counterclaim. However, it was acknowledged by counsel for the defendant/plaintiff by counterclaim that Dr Clarnette's proposed supplementary expert report was not yet finalised as there was a need for further correspondence sent to Dr Clarnette to be included as annexures to that report so as to comply with the Harmonised Expert Witness Code of Conduct.[26]
[26] ts 495 - 496, 504 - 505 (29 May 2025).
An application was made on behalf of the plaintiff/first defendant by counterclaim to adjourn the hearing of the application for leave given the late receipt of the latest draft of Dr Clarnette's proposed supplementary report dated 28 May 2025, and that Mr Shepherd was not yet in a position to properly address the application.[27] The requested adjournment was opposed on the basis that the 28 May 2025 draft was not substantially different to the 20 April 2025 draft of Dr Clarnette's proposed supplementary report which Mr Shepherd had since at least 7 May 2025.[28] Mr Shepherd did not agree with that characterisation.[29]
[27] ts 503 - 504 (29 May 2025).
[28] ts 495 - 496 (29 May 2025).
[29] ts 515 ‑ 516 (29 May 2025).
It was acknowledged by counsel for the defendant/plaintiff by counterclaim that the supplementary report of Dr Clarnette ought be filed in its final form with all necessary documents attached (that is, the instructions received), and I understood that Dr Clarnette would be asked to produce the same.[30]
[30] ts 509 (29 May 2025).
While conscious of the extraordinary amount of costs being incurred in the matter, it was appropriate to adjourn the application to allow time the defendant/plaintiff by counterclaim to file Dr Clarnette's proposed supplementary expert report in final form and to allow any supplementary submissions in opposition to the application to be filed. It was agreed by all counsel that the application ought then be determined on the papers, that is reflected in the orders made on 29 May 2025. (A copy of the orders made at that hearing on 29 May 2025 are attached as Sch A to these reasons.)

Final proposed supplementary report

In compliance with my orders made on 29 May 2025, on behalf of the defendant/plaintiff by counterclaim a further affidavit of Mr Sloan was filed, to which Mr Sloan attached the proposed supplementary expert report of Dr Clarnette dated 1 June 2025.
The proposed supplementary expert report of Dr Clarnette varied from the report admitted into evidence in that in his proposed supplementary report:
(a)Dr Clarnette acknowledged that he had read and agreed to be bound by the Harmonised Expert Witness Code of Conduct;
(b)under the heading 'Medical Problems' Dr Clarnette had included additional information as to the deceased's end state liver disease and end stage renal failure;
(c)reference to reliance upon the lay witness evidence of Ezio Celenza and Osvaldo Celenza was removed;
(d)as to whether the deceased was aware of the nature of the legal document, the opinion that had been expressed by Dr Clarnette as 'could not' was changed to 'is likely not to';
(e)reference to the last will and testament not having been provided to Dr Clarnette was removed;
(f)additional analysis supporting the conclusion reached and opinion expressed by Dr Clarnette was included; and
(g)Dr Clarnette included the word 'probably' in the following expression of his opinion, 'In my view the medical evidence alone supports the view that the deceased probably lacked testamentary capacity on 23 February 2016'. (emphasis added)
Like previous drafts of Dr Clarnette's proposed supplementary expert report, there was no change to the conclusion reached and opinion expressed by Dr Clarnette that '[i]t is more likely than not that the deceased lacked the capacity to properly execute a will on 23 February 2016'.[31]

Supplementary submissions

[31] Affidavit of JW Sloan sworn 3 June 2025, JS1 (page 8).

On 6 June 2025 the plaintiff/first defendant by counterclaim filed supplementary submissions in opposition to the application. The supplementary submissions were filed late. Orders extending time for compliance were made on 10 June 2025, unopposed by the defendant/plaintiff by counterclaim. At the hearing on 10 June 2025, both counsel reaffirmed that they were content for this application for leave to be determined on the papers filed.
I therefore had regard to all submissions filed both in support and opposition to the application for leave.

The position of the defendant/plaintiff by counterclaim

In summary, it is the position of the defendant/plaintiff by counterclaim that leave should be granted to file (and rely at trial upon) the supplementary expert report of Dr Clarnette dated 1 June 2025 for the following reasons:[32]
(a)no prejudice will arise to the plaintiff/first defendant by counterclaim;
(b)cross-examination of Dr Clarnette has not begun;
(c)the proposed supplementary expert report explains aspects of Dr Clarnette's first report, it does not introduce new matters of substance; and
(d)there is (and has been) opportunity for counsel for the plaintiff/first defendant by counterclaim to prepare for cross‑examination of Dr Clarnette, taking into account the proposed supplementary report.
[32] Defendant/plaintiff by counterclaim's submissions filed 20 May 2025 pars 13 - 14.

The position of the plaintiff/first defendant by counterclaim

In summary, it is the position of the plaintiff/first defendant by counterclaim that leave should be refused because the probate proceeding (that is, the counterclaim) is defective, alternatively there are no arguable grounds for the application.[33]
[33] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 2 - 3.
Through counsel, the plaintiff/first defendant by counterclaim submits that the pleaded counterclaim is incompetent as it was not commenced by writ as a separate action; failed to comply with the provisions of O 73 of the Rules of the Supreme Court; and was (purported to be) brought by the defendant/plaintiff by counterclaim. In that context, it was submitted that the application for leave to file a supplementary expert report was also incompetent and leave should not be granted.[34]
[34] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 par 2.
In the alternative, the plaintiff/first defendant by counterclaim maintained that there were no arguable grounds for the application for the following reasons.
First, the expert is required to comply with the Harmonised Expert Witness Code of Conduct. This includes the requirement that the expert read the provisions contained within before preparing a report to ensure that the report is prepared in accordance with that code.[35]
[35] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 4 - 6.
Secondly, the proposed supplementary report is not properly seeking to address supplementary matters but to remedy deficiencies in the original report.[36] The grant of leave to rely on a supplementary report should be constrained to circumstances where the expert changes his opinion on a material matter;[37] if new information has come to the attention of the expert;[38] or if the expert needs to deal with opinions of subsequent experts.[39]
[36] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 10 - 20.
[37] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 7 - 8.
[38] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 par 9.1.
[39] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 par 9.2.
Thirdly, it is impermissible as a matter of procedural fairness to have an expert witness remedy defects in their report in the manner proposed, particularly considering it is done so in advance of cross examination.[40]
[40] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 21 - 24.
Fourthly, because the defendant/plaintiff by counterclaim obtained the grant of probate, he should be the one to propound the will and bring expert evidence in support of the deceased's capacity. The failure to do so in circumstances where the plaintiff/first defendant by counterclaim is impecunious and all or most of the assets of the estate have been distributed, it is submitted causes procedural unfairness.[41]
[41] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 25 - 29.
Fifthly, even though the defendant/plaintiff by counterclaim was aware because of the objections made during the second day of trial that Dr Clarnette's report was deficient, that party failed to attempt to confer until May 2025, and then failed to lodge the application for leave to adduce further expert evidence until 14 May 2025. Given the delay of the defendant/plaintiff by counterclaim the plaintiff/first defendant by counterclaim only had two days to file and serve responsive submissions, and the delay in acting was not adequately explained.[42]
[42] Plaintiff/first defendant by counterclaims submissions filed 26 May 2025 pars 30 - 37.
The supplementary submissions of the plaintiff/first defendant by counterclaim included one further ground of opposition to the application which was that Dr Clarnette has materially changed his opinion on a fundamental matter, without having identified that change. It was noted as follows:[43]
[43] Plaintiff/first defendant by counterclaim's supplementary submissions filed 6 June 2025 pars 22 - 29, 38.
23.In the Second Paragraph on page 3 of the Report, Dr Clarnette said:
'She presumably had multiple organ failure, had been receiving opioid and benzodiazepine medication … every day since admission to Bethesda Hospital and could not have been aware of the nature of a legal document or what she was testifying to when she made her "mark".' (counsel's emphasis)
24.In the proposed Supplementary Report, Dr Clarnette has materially changed his opinion to read:
'She presumably had multiple organ failure, had been receiving opioid and benzodiazepine medication … every day since admission to Bethesda Hospital and is not likely to have been aware of the nature of a legal document or what she was testifying to when she made her "mark".'[44]
[44] This quote is not accurate, the emphasised text should read 'is likely not to'; see affidavit of JW Sloan sworn 3 June 2025, JS1 (page 8).
It was submitted that the change from 'could not' to 'is not likely to' is particularly important as the opinions expressed as to the deceased's capacity set out in the following paragraphs draw directly from that paragraph which has now been amended.[45]
[45] Plaintiff/first defendant by counterclaim's supplementary submissions filed 6 June 2025 par 25.

Applicable principles

The principles surrounding whether to grant leave to permit a party to adduce expert evidence were summarised by Smith J in McMurray v AIG Australia Insurance Ltd [No 4] [2020] WASC 210 in the following terms:
[30]In exercising the discretion as to whether to grant leave to permit a party to adduce expert evidence, and in determining where the interests of justice lie, the considerations explained in AON Risk Services Australia Ltd v Australian National University are to be taken into account.[46]
[46] AON Risk Services Australia Ltd v Australian National University [2009] HCA 27; (2009) 239 CLR 175 [89] ‑ [103] and [111] ‑ [112]; McKay v Commissioner of Main Roads [No 6] [2010] WASC 274 [18]; Hamersley Iron Pty Ltd v James [2015] WASC 10 [150]; Attorney-General of Botswana v Aussie Diamond Products Pty Ltd [2009] WASC 301 [80].
[31]In Hamersley Iron Pty Ltd v James, Beech J explained that when considering whether to grant leave to permit a party to adduce expert evidence, the relevant considerations referred to in AON Risk Services Australia Ltd v Australian National University could be summarised as follows:[47]
[47] Hamersley Iron Pty Ltd v James [150].
(a)the effect of an application to adduce further evidence on the court and on other litigants is relevant;
(b)there is no right to adduce all arguably relevant evidence, no matter the stage at which the application is made and no matter the effect upon the course of the litigation;
(c)justice requires that parties have a fair opportunity to adduce evidence in support of their case, but limits may be placed on late applications to adduce further evidence;
(d)the nature and importance of the proposed new evidence to the party seeking to lead it must be taken into account;
(e)attention must be given to the extent of the delay, and the costs associated with it, the prejudice which might reasonably be assumed to follow from that delay, and any prejudice that is shown;
(f)the point in the litigation relative to the trial may be an important consideration;
(g)where a discretion is sought to be exercised in favour of a party, an explanation will be called for; and
(h)the point can be reached where a party has had sufficient opportunity to adduce evidence in support of its case.
[32]Further, the AON Risk Services Australia Ltd v Australian National University principles require that in cases where an indulgence is sought, particularly in or close to the trial where there is an obvious potential for serious disruption to the litigation, there should be a proper explanation for the application, showing that it is brought in good faith and bringing to the court's attention, in a candid way, the circumstances giving rise to the application.[48]
[48] Attorney-General of Botswana v Aussie Diamond Products Pty Ltd [70].
In Treneer v City of Stirling [2002] WASCA 281, the Court of Appeal in the context of an appeal from the decision of the District Court to refuse to vacate a trial date, considered the role of the rules of expert evidence and how those rules interact with the conduct of solicitors and case management considerations. I note the following three points from that decision.
First, as counsel for the defendant/plaintiff by counterclaim emphasised, the purpose of the rules requiring disclosure of expert evidence is to ensure that there is no surprise at trial and the opposing party has opportunity to consider and if necessary answer expert evidence led by an opposing party.[49]
[49] Defendant/plaintiff by counterclaim's submissions filed 20 May 2025 par 11, citing Treneer v City of Stirling [33].
Secondly, the rules of evidence are not to be used as a tool to take advantage of an opponent's errors, incompetence or dilatoriness.[50]
[50] Treneer v City of Stirling [33].
Thirdly, case management principles should not be used as a tool to punish a party for mistakes made in the conduct of their own case.[51]
[51] Treneer v City of Stirling [36] - [38], citing Sali v SPC Ltd (1993) 67 ALJR 841, 849; Cropper v Smith (1884) 26 Ch D 700, 710; Clough & Rogers v Frog (1974) 48 ALJR 481; Queensland v JL Holdings Pty Ltd (1997) 189 CLR 146, 154, 155.
In the context of the delay of the provision of expert reports resulting noncompliance with trial directions, Kenneth Martin J in Moore v Landsdale Pty Ltd [2012] WASC 452 made the following observation (which I consider to be apt in the circumstances in which the defendant/plaintiff by counterclaim seeks leave in this matter):
[51]A court is traditionally reticent to prevent a party having its day in court and then, when it does, from putting its best foot forward in terms of adducing the best evidence available to it to support its case. A court is also loathe, in the interests of justice, to lay, at the doorstep of a party, possible faults, omissions or misdeeds of its legal advisers in carrying out their instructions or in timeously progressing a matter to trial. A court will usually weigh the possibility of an adjournment, or an adverse costs order in an attempt to redress a case management default, where it is in the overall interests of justice. But, as between parties in litigation, justice is not a one-way street. And, as the High Court explained in Aon Risk Services Australia Ltd v Australian National University [2009] HCA 27; (2009) 239 CLR 175, there are broader public interests at play than simply the interests of the particular parties in litigation.
I also note that in Attorney-General of Botswana v Aussie Diamond Products Pty Ltd [No 2] [2012] WASCA 73, Martin CJ discussed the role of O 4A of the Rules of the Supreme Court in the context of evidence from a witness whose statement has not been served in accordance with a timetable established under the direction of the trial judge, and in particular the following passage recorded at [145]:
Further, the case management regime established by O 4A of the Rules confers broad discretions upon a case manager to be exercised in the achievement of the overriding objectives specified in O 1. Those discretions will often be exercised by a case manager having regard to his or her particular knowledge of the pre-trial history of the proceedings and the conduct of the parties, and his or her assessment of the most appropriate way in which the overriding objectives can be achieved in that context.

Disposition

I proceed in the disposition of this application by addressing first the submission that it is not competent for the defendant/plaintiff by counterclaim to seek leave where the probate proceeding (as the counterclaim is described by the plaintiff/first defendant by counterclaim) is defective. I then turn to consider whether it is in the interests of justice to grant leave.
The question that I must ask is whether it is in the interests of justice to allow the defendant/plaintiff by counterclaim to adduce further expert evidence. I adopt and apply the principles that I have summarised from McMurray v AIG Australia Insurance Ltd [No 4] in answering this question, which requires me to balance the importance of the supplementary report to the defendant/plaintiff by counterclaim with the potential prejudice that the plaintiff/first defendant by counterclaim might suffer.
I had regard to all the applicable principles as summarised, and note that I am not required to determine whether the expert report is in fact admissible or the weight that I might give to it if it were tendered.

Defective probate proceeding

The counterclaim is described by the plaintiff/first defendant by counterclaim as the 'probate proceeding'. Whether it was defective was an issue first raised by the plaintiff/first defendant by counterclaim shortly after the counterclaim was filed on 16 August 2022. Complying with the orders of Registrar Fatharly made on 8 November 2022, the plaintiff/first defendant by counterclaim made an application by chamber summons filed on 22 November 2022 for judgment to be entered in her favour on the counterclaim, alternatively to strike out all or part of the counterclaim. By the consent of the parties the application before the Master was vacated prior to hearing, and adjourned sine die.[52]
[52] Orders 1 and 2 of the orders of Acting Master McDonald made 16 March 2023.

The same issue was again agitated at a case management conference before Registrar Fatharly on 28 May 2024, where the plaintiff/first defendant by counterclaim was ordered by 4.00 pm on 11 June 2024 to file any application by chamber summons for summary judgment or to strike out any part of the defence and counterclaim of the defendant/plaintiff by counterclaim. No application was made by 11 June 2024 or otherwise.
Consequentially, claims have been prosecuted and defences maintained on the understanding that the issue of the competency of the counterclaim was a matter in issue in the trial. This issue is a live one at trial and has been the subject of extensive submissions by the plaintiff/first defendant by counterclaim in counsel's opening address and written outline of opening submissions for trial.[53]
[53] First defendant by counterclaim's outline of submissions filed 25 March 2025.
The plaintiff/first defendant by counterclaim now resists the application to adduce supplementary expert evidence grounded on a matter which is to be determined at trial. I do not consider that resistance on the ground of the counterclaim being defective is a matter which I can properly consider in the context of this application for three reasons.
First, if I was to make a finding as to the issue in this application, it would have the effect of summarily determining a pleaded and contested issue which is being argued and remains a live issue in a part heard trial. While often discussed in the context of interlocutory injunctions, generally interlocutory applications are not the forum for determining contested issues of law and fact between the parties which are to be properly ventilated at trial.[54] This is because doing justice between the parties requires me to have permitted both parties to have adduced evidence and made submissions prior to making findings as to questions of law and fact. In the context of the present application, the trial remains part heard with the defendant/plaintiff by counterclaim to adduce further evidence, and thus it is inappropriate for me to make findings of fact or law at this stage as promoted by the plaintiff/first defendant by counterclaim in opposition to this application.
[54] See Life Combat Sports Pty Ltd v The World Institute of Martial Arts [2025] WASC 21 [73], [126], citing Warner‑Lambert Company LLC v Apotex Pty Ltd [2014] FCAFC 59; (2014) 311 ALR 632 [72], [91]; Emeco International Pty Ltd v O'Shea [2012] WASC 282 [24].
Secondly, in the context of an application for leave to adduce further expert evidence, the issue to be determined by the exercise of discretion is whether it is in the interests of justice to allow further evidence to be adduced. In such an exercise I do not consider it appropriate to determine the cogency of the defence and counterclaim that the expert evidence is intended to be relied upon to support. The very purpose of expert evidence sought to be adduced is to prove a pleaded fact. To not allow a party to present that evidence because it is intended to be relied upon to support what is submitted to be an incompetent defence or counterclaim (which remains a live issue) is an impermissible outcome.
Once properly ventilated at trial, if the counterclaim is found, as a matter of law, to have been properly pleaded, to have refused leave on the first ground advanced by the first defendant to the counterclaim in opposition to the application would result in injustice to the plaintiff by counterclaim.
Thirdly, the plaintiff/first defendant by counterclaim has had ample opportunity to prosecute an application for summary judgment or to strike out all or part of the counterclaim. Such application was not prosecuted. It appears from the court record that an election was made on the part of the plaintiff/first defendant by counterclaim not to seek summary adjudication of the point. The issue now stands to be determined at trial, and as such, I make no finding at this time as to the same.
I consider that it is competent for the defendant/plaintiff by counterclaim to bring this application for leave.
The plaintiff/first defendant by counterclaim suggests that because of the defendant's role in the probate proceeding (that is, the counterclaim), it is procedurally unfair for the defendant/plaintiff by counterclaim to seek leave to adduce further expert evidence. This appears to be grounded on the submission that the plaintiff/first defendant by counterclaim is not a proper respondent to the counterclaim, and that by bringing the counterclaim purportedly in his capacity as an executor (having distributed all or most of the assets and having cast the action to challenge the will (improperly) as a counterclaim), the defendant/plaintiff by counterclaim has effectively denied the plaintiff/first defendant by counterclaim the benefit of an executor who would defend the will he propounded.[55] For the same reasons as expressed above, I consider that this application is not the appropriate forum to ventilate or determine such issues.

Interests of justice

[55] Plaintiff/first defendant by counterclaim's submissions pars 25 - 29.

In determining where the interests of justice lie, I weigh the following in the balance.
First, the supplementary report does not record a change in the ultimate opinion expressed and conclusion reached by Dr Clarnette. What is sought to be remedied are deficiencies in his previous report, particularly by providing an explanation of how Dr Clarnette came to hold the opinion he had expressed.
The plaintiff/first defendant by counterclaim submitted that the lack of change to the conclusion reached by the expert is one reason why leave should be refused, as fixing defects in an original report it is not a permissible ground to allow a supplementary report to be adduced.[56] The plaintiff/first defendant by counterclaim says that this is because the Harmonised Expert Witness Code of Conduct and other recognised uses for supplementary reports do not cover or extend to such a change.[57]
[56] Plaintiff/first defendant by counterclaim's submissions pars 22 - 23.
[57] Plaintiff/first defendant by counterclaim's submissions pars 7 - 10.
I do not consider that the Harmonised Expert Witness Code of Conduct should be read as prescriptive as to the circumstances where an expert can provide a supplementary report. Paragraph 4 of that Code which the plaintiff/first defendant by counterclaim suggests imposes some restriction, cannot be properly construed in such a manner. Paragraph 4 provides that:
Where an expert witness has provided to a party (or that party's legal representative) a report for use in Court, and the expert thereafter changes his or her opinion on a material matter, the expert shall forthwith provide to the party (or that party's legal representative) a supplementary report which shall state, specify or provide the information referred to in subparagraphs (a), (d), (e), (g), (h), (i), (j), (k) and (l) of par 3 of this Code and, if applicable, subparagraph (f) of that paragraph.
I consider it appropriate that par 4 of the Code be read with par 5 which provides as follows (my emphasis):
In any subsequent report (whether prepared in accordance with par 4 or not) the expert may refer to material contained in the earlier report without repeating it.
It is clear that the Harmonised Expert Witness Code of Conduct contemplates experts preparing a subsequent report outside the bounds of par 4 by inclusion of the words 'or not' in par 5.
While I accepted the submission made by the plaintiff/first defendant by counterclaim that supplementary reports might be used to address new information that has come to the attention of the expert and explain if and how that new information affects the conclusions made in the original report; to address opinions contained in a report prepared by a second or subsequent expert; or if an expert changes their option,[58] I see no reason why the Code ought be read so as to curtail the expert from providing an expert report to correct or supplement a previous report, nor is there by caselaw curtailing of the circumstances which might properly give rise to a desire on the part of an expert to correct or supplement. In fact, commentary suggests that a supplementary report may be prepared because of the 'discovery of an error'.[59]
[58] See Freckelton I, Expert Evidence: Law and Practice (at 6 June 2025) [5.0.140] citing Anderson v Minister for Infrastructure Planning & Natural Resources [2006] NSWLEC 725; (2006) 151 LGERA 229; Harrington-Smith v Western Australia (No 9) [2007] FCA 31; (2007) 238 ALR 1.
[59] Freckelton I, Expert Evidence: Law and Practice (at 6 June 2025) [5.0.140].
I consider that the question of whether a supplementary report should be admitted where it remedies an error or omission in a previous report is a question which ultimately turns on the importance of the supplementary report and the effect on the plaintiff/first defendant by counterclaim.
Secondly, I do not consider that a party's legal representatives should be prevented from requesting an expert provide a supplementary report in circumstances where the supplementary report is directed at remedying defects or omissions in the original report. The role of legal practitioners in the preparation of expert reports is one which permits this to occur.
In Harrington-Smith v Western Australia (No 7) (2003) 130 FCR 424 at [19], Lindgren J said as follows:
Lawyers should be involved in the writing of reports by experts: not, of course, in relation to the substance of the reports (in particular, in arriving at the opinions to be expressed); but in relation to their form, in order to ensure that the legal tests of admissibility are addressed.
In Landel Pty Ltd v Insurance Australia Ltd [2021] QSC 247, Dalton J said:
[19]First, while lawyers must not coach expert witnesses, or influence the substance of an expert report so that it favours their client, it is permissible, and usually desirable, that lawyers do become involved in the editing of expert reports so that they present material in a way which is accessible and comprehensible, and do not contain irrelevant material. …
…
[21]Any disciplined and structured conferences with [the expert] would have revealed that there were faults in his opinions which went beyond matters of expression and presentation. They would have revealed significant contradictions, errors and gaps in reasoning in his reports. It is permissible for matters of substance like this to be drawn to an expert's attention in conference with lawyers, and remedied if the expert is able and willing to do so. Again, coaching is not permitted, and drafts will be disclosable.
It is clear that the role of legal practitioners extends to ensuring that errors and gaps in reasoning (of the type sought to be remedied in the supplementary report of Dr Clarnette) is permissible, even encouraged, to ensure that the court does not have its time wasted by reports that are poorly written and fail to deal properly with matters in issue. What the solicitors for the defendant/plaintiff by counterclaim cannot do is act in a manner which would influence the substance of an expert report so as to impugn the expert's independence. On the evidence before me there is nothing to suggest that Dr Clarnette's evidence is not independent or that the solicitors for the defendant/plaintiff by counterclaim have acted improperly. These are matters which, if they are to arise in the course of evidence, may be dealt with in the cross‑examination of Dr Clarnette. As such, I consider it was appropriate for the defendant/plaintiff by counterclaim to request that he remedy omissions identified in his previous report (albeit that request was made late in the conduct of the proceedings).
Thirdly, I accept that there has been a change to the opinion of the expert. Dr Clarnette originally opined that because of the deceased's condition, she 'could not have been aware of the nature of a legal document or what she was testifying to when she made her "mark"'.[60] Dr Clarnette in his supplementary report changed the words 'could not' to 'is likely not'. The change reflects a change in the degree of certainty of Dr Clarnette in his opinion in that regard. The phrase 'could not' appears to impose a higher degree of certainty than 'is likely not'. As such, I am satisfied that there has been a change. The report does more than simply add previously omitted reasoning.
[60] Affidavit of JW Sloan sworn 3 June 2025, JS1 (page 8) (my emphasis).
I infer from the supplementary submissions filed on behalf of the plaintiff/first defendant by counterclaim that the issue with this change is that it is a change in opinion made without explanation.[61]
[61] Plaintiff/first defendant by counterclaim's supplementary submissions filed 6 June 2025 par 38.
It is well established that it is legitimate for experts to change their opinion, as was noted by Habersberger J in Orrong Strategies Pty Ltd v Village Roadshow Ltd (2007) 207 FLR 245 at [985]:
I also consider that experts should be entitled to think through the issues and change their mind without being castigated for giving into pressure from the client or lawyers.
A change in opinion may affect the expert's credibility, particularly if there is a lack of sound basis for the change.[62] The consideration of the expert's credibility is however a matter to be considered at trial, and as such, I did not weigh this matter particularly in the balance as to whether to grant leave, and I make no findings as to the same. However, I do consider that the fact that Dr Clarnette had changed his opinion in this manner to one that ought be considered as to whether there is prejudice which flows from a grant of leave to adduce that further expert evidence. The change was noted and from the submissions filed, clearly appreciated by Mr Shepherd. I also note that Mr Shepherd as counsel had been on notice of the change from at least 6 June 2025, as it is noted in the supplementary submissions filed on that date.[63] I weigh the fact of the change in the balance.
[62] Freckelton I, Expert Evidence: Law and Practice (at 6 June 2025) [7.0.400], citing Seeley International Pty Ltd v Jeffrey [2013] VSCA 288.
[63] Plaintiff/first defendant by counterclaim's supplementary submissions filed 6 June 2025 pars 23 - 24.
Fourthly, I accept that the change was not identified or acknowledged by the defendant/plaintiff by counterclaim expressly in the application or the affidavits filed in support of the same. The defendant/plaintiff by counterclaim's outline of opening submissions at par 7 records as follows:
The Supplementary Report is in substance no different from the First Report. It provides additional analysis and reasoning, directed to the same opinion and conclusion as is the First Report.
This characterisation (for the reasons already provided) is not strictly correct.
The plaintiff/first defendant by counterclaim submits that there is an obligation on the expert to explain a change in their opinion to the court and parties in a supplementary report.[64] This submission was developed in the plaintiff/first defendant by counterclaim's application for an extension of time to file her supplementary submissions in opposition to the application, reproduced below:[65]
Where an expert has prepared and filed a report, and materially changes his opinion, the Harmonised Expert Code of Conduct rules require him to produce a supplementary report expeditiously, informing the court and the parties that the report is required as soon as possible and serving the report without delay.
[64] Plaintiff/first defendant by counterclaim's supplementary submissions filed 6 June 2025 par 25.
[65] Letter application for extension of time to file submissions in opposition filed 9 June 2025, page 2.
I accept that there is an obligation on an expert arising out of par 4 of the Harmonised Expert Witness Code of Conduct to provide the party who requested the original report with a supplementary report in circumstances where that witness has changed their opinion. What is clear in that paragraph is that there is an obligation on a witness who changes their opinion to provide a supplementary report. This does not appear to be an instance where Dr Clarnette changed his opinion and failed to provide a supplementary report, rather it would appear that Dr Clarnette has changed his opinion in the course of producing a supplementary report. In this regard, I note that Dr Clarnette was instructed to explain more fully his analysis at arriving at his opinion and conclusion, as requested of him in the letter requesting that he produce a supplementary report.[66]
[66] Affidavit of JW Sloan sworn 12 May 2025, JS1 (page 11).
It is desirable that experts who change their opinion explain why they have changed their opinion. It is also desirable for experts to note that their opinion has in fact changed. However, a supplementary report was provided, the change was made, and while it was not highlighted, it was in fact identified and noted by counsel for the plaintiff/first defendant by counterclaim, and the plaintiff/first defendant by counterclaim is clearly on notice of that change. As such, while I weighted the plaintiff/first defendant by counterclaim's submission in the balance, I did not consider the failure to highlight the change to be fatal to the application.
Fifthly, the supplementary report is important to the defendant/plaintiff by counterclaim. As was identified by the objection taken to the tender of Dr Clarnette's first report and my ruling as to the same, the first report appeared to lack some analysis (which counsel for the plaintiff/first defendant by counterclaim drew the court's attention to and which might effect the weight which can be given to the opinions there expressed). I expressly caveat my observations in this regard. Dr Clarnette's first report has been tendered and his evidence is not complete. The defence to the action, put succinctly, concerns the capacity of the deceased and her knowledge of the 2016 will. The counterclaim also concerns the same. The grant of probate for the 2016 will is sought to be set aside and an order made pronouncing the force and validity of an earlier will. The expert evidence of Dr Clarnette goes directly to the material facts pleaded and matters that are in issue, and being the only expert evidence intended to be adduced, appears to be of vital importance to the disposition of the substantive issues at trial.
In this respect, I adopt the comments made by Kenneth Martin J in Moore v Landsdale Pty Ltd at [51] that the court is reticent to prevent a party having its day in court and then, when it does, from putting its best foot forward in terms of adducing the best evidence available to it to support its case. This is a factor which weighs heavily in the disposition of this application.
Sixthly, the changes considered as a whole are not cumbersome or result in any substantive prejudice to the plaintiff/first defendant by counterclaim. While important potentially to the disposition of the trial, the supplementary report and changes made are not voluminous. The largest change by way of volume is the inclusion of a half page explanation of how Dr Clarnette reached his conclusion. It cannot be described as being cumbersome to the plaintiff/first defendant by counterclaim. This is not a change which fundamentally changes the expert's evidence, in the sense of a change of the ultimate opinion expressed or conclusion reached, as distinct from reasoning and opinions which ground that conclusion. As such, I do not accept that the plaintiff/first defendant suffers prejudice (otherwise than by the complaint that a forensic advantage obtained if the first report only was tendered would be lost).
Further, the material change is one which, while I do not make a finding as to its effect, may possibly favour the plaintiff/first defendant by counterclaim, insofar as Dr Clarnette expressed less certainty in his view.

Seventhly, the plaintiff/first defendant by counterclaim has been on notice of the possibility of a supplementary report being produced since 27 March 2025. The plaintiff/first defendant by counterclaim had an early copy of a draft supplementary report since 7 May 2025. While the report now submitted as the final supplementary expert report of Dr Clarnette does vary from the version provided to Mr Shepherd as counsel for the plaintiff/first defendant by counterclaim on 7 May 2025, the only difference of any consequence is the addition of one dot point which identifies examinations, tests or other investigations on which the expert relied and identified the persons who carried them out and those persons' qualifications. That was a change which had been requested of the expert by the solicitors for the defendant/plaintiff by counterclaim and which request the plaintiff/first defendant by counterclaim was aware on 7 May 2025.[67] The inclusion of the requested change in the final report is no surprise. The plaintiff/first defendant by counterclaim has had opportunity to prepare in light of the same.
[67] Affidavit of JW Sloan sworn 12 May 2025, JS1 (pages 7, 19).
Further, while counsel for the plaintiff/first defendant by counterclaim complains that the expert changed his opinion (which was only discovered in the text of the document while checking and thus Mr Shepherd was unable to file supplementary submissions on time) the change complained of was present in the draft report provided to the plaintiff/first defendant by counterclaim on 7 May 2025.[68] I note that the report was only three and a quarter pages long, and counsel for the plaintiff/first defendant by counterclaim has had since 7 May 2025 opportunity to consider the same.
[68] See [91] above and the affidavit of JW Sloan sworn 12 May 2025, JS1 (page 9).
Eighthly, the supplementary report is undoubtedly provided late. There was the delay in making the application for leave to adduce further expert evidence and then the delay in the provision of the final proposed supplementary expert report.
There was significant delay in the provision of the final version of the proposed supplementary expert report (having been provided some 10 days prior to the recommencement of trial). That said, the plaintiff/first defendant by counterclaim has not identified how this would cause any impact on the trial dates or for that matter, any particular prejudice. There is no need to recall Dr Clarnette as his cross examination is yet to commence. The trial was adjourned part heard for reasons not caused by the proposed tender of a supplementary report. It is not suggested that there is any need to recall witnesses or make changes to the trial timetable. I accept that the plaintiff/first defendant by counterclaim will have had opportunity to prepare for the cross examination of Dr Clarnette by the time trial recommences on Friday. This weighs heavily in the balance in favour of the grant of leave.
Ninthly, the defendant/plaintiff by counterclaim has failed to provide an explanation for the delay. I accept that it is well established that there is a need to provide that explanation. However, whether the failure to explain the delay will be fatal must depend on all of the circumstances.
The delay in seeking leave to adduce further expert evidence appears to be explained by the fact that the defect in the report was only understood upon objection being taken to the tender of Dr Clarnette's first expert report.
The delay in the making of an application and providing a finalised supplementary expert report appears to have been brought about (at least in part) because of Dr Clarnette's leave and because there was a need (as reflected in the materials before the court) to request on multiple occasions that Dr Clarnette make changes to his report to ensure all letters of instruction were annexed to his report and the Harmonised Expert Witness Code of Conduct matters were addressed. In all of the circumstances, I did not consider the delay to be determinative of the application.
Tenthly, I accept the submission made by the defendant/plaintiff by counterclaim that the objectives of the rules of expert evidence are to ensure that there is no surprise at trial and the opposing party has opportunity to consider and if necessary, answer expert evidence led by an opposing party. I consider that granting leave in the present circumstances would not infringe those objectives.
Eleventhly, I consider that the case management objectives found in O 1 r 4A and r 4B of the Rules of the Supreme Court will not be infringed by the grant of leave. These overriding objectives are designed to ensure the efficient and timely disposal of business, but also the just determination of litigation. As the grant of this application will not affect the trial dates set, and having regard to my knowledge of the history of this matter (including that the trial had been adjourned part heard and had been listed to recommence on 13 June 2025 for reasons wholly unrelated to this application), I do not consider the objectives to be infringed.
Twelfthly, I consider that the forensic advantage that is sought to be protected by the plaintiff/first defendant by counterclaim is not a sufficient reason to refuse the application. I am loath to deny the defendant/plaintiff by counterclaim the benefit of a further expert report in circumstances where the omissions sought to be corrected might have been properly identified by his legal advisors earlier and are now sought to be remedied in a manner which will not meaningfully prejudice his opponent and may ultimately lend to justice being done between the parties. In this sense, it appears that by the supplementary expert report, omissions which the solicitors for the defendant/plaintiff by counterclaim should have recognised and requested Dr Clarnette to remedy earlier are now sought to be remedied. The omissions are proposed to be remedied in a manner which does not impact the trial dates nor pose any material disadvantage beyond the loss of the forensic advantage.
In the end, there is a need to balance the importance of the supplementary report with the potential prejudice that the plaintiff/first defendant by counterclaim might suffer. On balance, having weighted all of the matters I have now summarised, having given careful consideration to all submissions filed, the history of the proceeding and trial, and in light of case management objectives imposed by the Rules of the Supreme Court, I considered that discretion ought be exercised to allow the application.

Conclusion and orders

For these reasons the defendant/plaintiff by counterclaim shall have leave to file and rely upon the supplementary expert report of Dr Roger Clarnette dated 1 June 2025, attached to the affidavit of Jamie William Sloan sworn on 3 June 2025. I am prepared to make an order to that effect.
While I will grant the leave sought, I make no finding as to the weight that might be given to the evidence of Dr Clarnette if the supplementary report is in fact tendered. That is a matter for trial.
I will also order that the costs of the application be reserved to the trial of the action.

Sch A - Orders made on 29 May 2025

I certify that the preceding paragraph(s) comprise the reasons for decision of the Supreme Court of Western Australia.
CR
Associate to the Honourable Justice Strk
9 JULY 2025