Miller Heiman Pty Ltd v Sales Principles Pty Ltd

The appeal concerned a dispute between Miller Heiman Pty Ltd (appellant) and Sales Principles Pty Ltd (respondent) before the New South Wales Court of Appeal. The primary judge had made certain judgments and orders, which the appellant sought to challenge. The appellant had also filed a motion for a new trial, which was dismissed by the primary judge.

The Court of Appeal was required to determine whether the primary judge had failed to consider a pleaded defence of estoppel by convention. It also had to consider the appropriate procedural avenue for addressing this omission, specifically whether a motion for a new trial or an application to set aside the judgment was more suitable. Furthermore, the Court had to decide whether to remit the matter to the primary judge for determination of the estoppel defence or to determine it itself.

The Court held that the primary judge had not determined the appellant's defence of estoppel by convention. It found that an application to set aside the judgment under rule 36.36 of the Uniform Civil Procedure Rules 2015 (NSW) was the appropriate procedural mechanism, rather than a motion for a new trial, as the integrity of the hearing was not questioned. Applying the principles of estoppel by convention, the Court noted that a claimant must demonstrate they would have acted differently but for the common assumption. As the determination of the estoppel defence did not involve assessing witnesses' demeanour, the Court of Appeal considered it appropriate to determine this defence itself.

The Court of Appeal allowed the appeal, set aside the primary judge's judgments and orders, and entered judgment for the appellant in the proceedings commenced by the respondent. The respondent was ordered to pay the appellant's costs of the appeal, the cross-appeal, and the proceedings at first instance. The appellant's application for leave to appeal from the interlocutory judgment dismissing its motion for a new trial was dismissed.