That passage was approved by Gibbs ACJ in Deaves v CML Fire and General Insurance Co Ltd (1979) 143 CLR 24 at 42. In Commonwealth v Verwayen (1990) 170 CLR 394, Mason CJ said that "waiver is an intentional act done with knowledge whereby a person abandons a right by acting in a manner inconsistent with that right" (at 406). Toohey J said that "waiver … may be found in the deliberate act of a defendant not to rely upon a defence available to him" (at 473). See also per Brennan J (at 427), Dawson J (at 451), Gaudron J (at 485). In Presmist Pty Ltd v Turner Corporation Pty Ltd (1992) 30 NSWLR 478 at 486, Cole J held that there was no waiver of a contractual provision because there was no "specific, conscious, demonstrated surrender of the right conferred by cl 42 to cancel the contract".
41 Often the construction of a document or the explanation of conduct said to constitute such an express or implied waiver, or to substantiate a conventional estoppel, can give rise to a degree of doubt as to its having that consequence. In those cases, it would be inappropriate for the present equivalent of interlocutory proceedings to attempt any final conclusion resolving that doubt, certainly in the case where the full extent of that evidence is unlikely to be forthcoming before the substantive trial. Essentially, the Court has to decide whether the only possible conclusion in the circumstances is that contended for by the party, here the Defendant, whose statutory demand is the subject of a claimed genuine dispute. It is not enough, in other words, for the Defendant merely to have the better of the argument at this point unless the balance in favour of the Defendant could not be expected to be affected by further possible evidence as might substantiate a different construction.
42 The present case is one where the proposition of waiver or conventional estoppel is based on the letter and Summary, as applied to the actual facts. As so advanced by the Plaintiff, I am satisfied that the argument for waiver fails to rise even to the modest level of a plausible contention requiring further investigation, when regard is had to those documents themselves in their context. The starting point is the covering letter of 18 November 1998. It can be taken that Woden Contractors Pty Limited, the company whose director wrote the letter, is closely associated with the Defendant. That letter states, as the Master has properly emphasised, that "this letter and the attachment do not waive, limit or vary any rights Wodens may have under the Deed of Acknowledgment or any other document referred to in, or contemplated by it".
43 It was acknowledged by the Plaintiff that the company search earlier referred to of both the Defendant and of Woden Contractors Pty Limited (earlier included under the expression "Wodens" in the second paragraph of the letter) disclosed that they shared a common director and there was no suggestion that Wodens was not here speaking for the Defendant as well. As I have earlier pointed out, Mr Fryer the director who signed the letter is also a director of Tatebrook, the Defendant, and there is no issue taken as to the share ownership in Tatebrook ultimately residing in the Woden group. Thus the letter, including the disclaimer quoted as well as the Summary which formed an attachment, can be taken to embrace Tatebrook.
44 The actual Summary apart from recording the actual date that the Gordon shops were sold and the Carwoola Street Sale Agreement was completed as being 3 December 1997, contains the important provisions of clause 4, not referred to in the Plaintiff's argument at all:
"4.1 LAND AWB and JB entered into the Lidoform Share Sale Agreement as vendors in favour of Contractors or its nominee as purchaser on 17 September 1997. In relation to that agreement
(a) Conditions Precedent 13.3(a), (c), (e) and (f) of the Deed of Acknowledgment have not been satisfied ;
(b) The Conditions Precedent to completion of the Lidoform Share Sale Agreement set out in clause 13.3(a), (c) and (e) of the Deed of Acknowledgment can no longer be satisfied as timing requirements relating to those Conditions Precedent are not capable of being satisfied ; and
(c) The release in clause 13.4 of the Deed of Acknowledgment has not taken effect."
[my emphasis]
45 There could hardly be a clearer or more emphatic statement that the relevant condition precedent not only has not been satisfied but can no longer be satisfied with the consequence that the release has not taken effect and cannot now take effect.
46 But then finally one comes to clause 14 which, for convenience, I quote again:
"The Conditions Precedent (as defined in the Idogear Deed of Assignment) have been satisfied and accordingly on the First Stage Completion Date, Tatebrook assigned to Idogear all its right, title and interest in so much of the LAND Debt to Tatebrook as is set out in item 2 of the schedule to the Idogear Deed of Assignment (being $600,000). Otherwise the Idogear Deed of Assignment continues in full force and effect."