"21 It was next submitted that the relief sought in the 1999 proceeding should be refused as the matter was res judicata. This cannot be correct. No substantive judgment was given against the Hopkins in the 1993 proceeding. There is, therefore, no judgment into which Mr King's causes of action against them have merged 22 The submission based on the rule expounded by the High Court in Port of Melbourne Authority v Anshun Pty Ltd [1981] HCA 45; (1981) 147 CLR 589, fastens upon the other aspect of the finality of court judgments, the avoidance of multiplicity of proceedings. It is that a party should not be permitted to return to the court to raise an issue which had not been but which ought properly to have been raised in the earlier proceeding. The applicable principle depends upon unreasonableness. `There will be no estoppel unless it appears that the matter relied upon as a defence in the second action was so relevant to the subject matter of the first action that it would have been unreasonable not to rely on it': Port of Melbourne Authority v Anshun Pty Ltd [1981] HCA 45; (1981) 147 CLR 589 at 602, per Gibbs CJ, Mason, Aickin JJ. The principle has been applied equally to cases where it is the claimant and not the defendant who seeks to raise an issue in the later proceeding. See Terry v Permanent Trustee Australia Ltd (1995) 6 BPR 14,091 at 14,103 and the cases there cited. In Bill Gibbs & McAllion Lloyd Pty Ltd v Kinna [1998] VSCA 52, Ormiston JA at [2] and Kenny JA at [23] applied to such a case the test whether or not it was unreasonable for the plaintiff asserting a cause of action in the second proceeding not to have asserted it in the earlier proceeding. It was not necessary for Kenny JA to determine whether the test was a narrower one, as to which see also Phillips JA at [6]. 23 In this case, the difficulty is that, in his statement of claim, Mr King did assert as a cause of action against the Hopkins that they were in breach of fiduciary duty. Why he did so, seeking only declaratory relief, is not altogether clear. Hedigan J was asked on 4 December 1992 to permit the joinder of the Hopkins, as defendants, on the basis that this was necessary because Lintrose as sole defendant denied that either of the Hopkins was its officer or employee. The transcript of the application made on that date was in evidence but it does not shed much light on this matter. It seems likely that the plaintiff's claim against Lintrose was then seen as depending upon proof of breach of fiduciary duty by Hopkins & Co. with whom Mr King had a contract and that Lintrose was the knowing recipient of the benefit of this breach. As originally pleaded, it was apparently not thought necessary to have Hopkins & Co. as a defendant, perhaps because there was no doubt about the retainer. But when the association of the Hopkins with Hopkins & Co. was put in issue, those advising Mr King must have thought it prudent to have them as parties, against whom similar breaches were alleged, again with the substantive relief sought only against Lintrose. 24 The question which counsel for the Hopkins would raise about the decision of Mr King at this time not to seek equitable compensation against their clients is this. Was this relevant to the subject matter of the 1992 proceeding? Was it unreasonable for Mr King not to seek and obtain such an order? To my mind each question must be answered in the negative. His claim in the 1992 proceeding was to undo the contract of sale which had been procured by the breach of fiduciary duty by the Hopkins. As things then stood, there is, subject to one matter, no evidence to suggest that such an order obtained and implemented would not have provided a satisfactory result. The matter I have referred to is the cross-appeal. Whatever its prospects of success, the fact that it was brought on 15 June 1993 suggests that, on that date, Mr King wanted more than the mere reversal of the sale. Notwithstanding this, I am not satisfied that Mr King acted unreasonably in pursuing Lintrose alone in the first proceeding. The submission based on the Anshun estoppel must, likewise, fail."