Facts
5 In late 2000 Austcorp was experiencing financial difficulties. Mr Dobson spoke to Mr Senes of Forte about someone taking over the lease. A Mr Felix Lyle of Kalset Pty Ltd ("Kalset") was introduced to Mr Dobson. There was a meeting with Mr Senes concerning assignment of the lease by Austcorp to Kalset, at or following which Mr Senes conveyed Forte's agreement to the assignment. In about the middle of December 2000 Austcorp went out of possession and Kalset went into possession, and with Mr Senes' consent Kalset was given keys to the premises. A letter was written and telephone calls were made in the latter part of December 2000 with a view to the assignment of the lease.
6 This is but a summary, and it is not easy to distil precise findings from the judge's reasons. The summary is sufficient, because it was common ground in the appeal that Austcorp, Kalset and Forte all contemplated that the lease would be assigned by Austcorp to Kalset and that the change in possession was in anticipation of the assignment of the lease.
7 In the early part of January 2001 Kalset paid $15,000 to Forte in cash. Although it was described as a bond, the $15,000 was credited as rent. Kalset paid two further sums of $7,050 and $7,750 to Forte. While the figures were not clear, it was accepted that rent was paid to about the end of May 2001.
8 For reasons which it is not easy to understand, Austcorp through Messrs George and Dobson expected that Mr Senes would arrange the documentation for the assignment of the lease, and Mr Senes appears initially to have undertaken to do so. He did not do so. That brought a letter of 11 January 2001 from Mr George to Mr Senes, which was much relied on in the appeal and should be set out in full -
"It is now several weeks since the new tenants moved into the above premises. Despite repeated requests by myself and Mr Allan [sic] Dobson for formal documentation of the assignment of the lease we have received no correspondence from your or your solicitors.
I am not prepared to continue to wait for the promised documentation. I formally give you notice that Alan Dobson and myself no longer accept that our guarantees of the lease of the above premises all [sic] in force, or take any further responsibility for the obligations contained in the lease.
You still retain the Bond money we paid to you even though the new tenants have paid a new bond. Mr Dobson and myself have received no payment for the fixtures, fittings and improvements made to the premises. We have agreed the terms of the assignment and you have accepted the covenant and rental from the new tenants. You cannot hold Alan and myself as guarantors simply by not issuing formal documentation, which we have undertaken to sign subject only to our solicitors approval that it fairly represents the agreement reached between us."
9 There was no reply to this letter, and nothing was done.
10 Under the lease rent had to be "at all times paid up three (3) months in advance" (cl 16.2). Presumably because it was not, on 16 March 2001 Mr Senes sent a note to Mr George stating that Kalset was behind in the rent and that he "call[ed] on you as guarantor to meet the rentals". Mr George's response included -
"During the course of the new tenants moving into the above premises, Alan Dobson and I made several requests for a proper assignment documentation. At all times I was told that the solicitors were dealing with the matter. In frustration I wrote to you on the 11th January 2001, a copy is attached, but received no reply.
I am advised that since you have allowed the new tenant to take possession, have accepted the rent and agreed to document the assignment, it is neither fair or acceptable for you to now expect to rely on my guarantee simply because you will not issue the appropriate assignment document and are endeavouring 'to have your cake and eat it'.
I reiterate that I do not accept that my previous guarantee is still in force. If you insist on taking the matter further please address all future correspondence to my solicitors, Messrs Uther Webster and Evans of Level 2, 235 Clarence St, Sydney NSW 2000 marked to the attention of Ms V Evans."
11 Mr Senes replied on 27 March 2000. He asserted that the guarantors would remain liable despite any assignment. He also appeared to assert that because it had not been documented there had not yet been an assignment, but also that an assignment was still intended; his letter included -
"We will keep you informed if matters are not concluded, only, if and when the payments are made regularly, will we consider an assignment and your guarantees will remain in force during the term of the lease." (emphasis in original)
12 Mr George's response in early April 2000 reiterated his earlier position.
13 On 20 April 2001 Mr Senes wrote to Messrs George and Dobson saying that Kalset was still in default as to rent and requiring payment from them as guarantors. The letter included, referring to Kalset -
"They handed us back the keys on the 19th April, 2001 and for extra security we changed the locks today. The keys are at our office for your collection or can be mailed to you on request."
14 The implicit invitation to go back into possession was not taken up. Mr George replied on 2 May 2001 on behalf of himself and Mr Dobson -
"We have repeatedly informed you both verbally and in writing that we do not accept liability for the lease of the above premises, for the reasons already given to you.
Further, from enquiries I have made since receiving your letter, I have reason to believe that the facts are not as you claim. The tenants wish to remain and rents have been paid though, admittedly not in a timely manner. If you have decided to take possession on the basis that you can take unreasonable and wrongful advantage of Mr Dobson and myself that is your decision.
I can only reiterate that if you wish to proceed with claims against Mr Dobson and myself, please contact our lawyers, of whom you have already been advised."
15 It was not contended in the appeal that Forte had "take[n] possession" as suggested in this letter, as distinct from Kalset giving up possession as stated in Mr Senes' letter of 20 April 2001.
16 In mid-May 2001 Forte placed the premises with an agent for re-letting. The premises were advertised by the agent in newspapers, on a website, by window display and by a sign on the building. Mr Senes agreed in cross-examination that he "took the view that it was [Forte's] right to lease or not lease the premises as it saw fit", but said that he believed he had a responsibility to mitigate Forte's loss. Some offers were received, and some negotiations eventuated but came to nothing. Austcorp was not told of the negotiations. In cross-examination Mr Senes said that he saw no need to tell Austcorp until "something was much closer to being - coming to fruition".