The answer may be that the contract is entirely unenforceable. In Khan [2006] the situation described here actually happened, with both sides having exchanged on the basis of slightly different draft transfers (one side had made amendments, but those had not been approved by the other side). What the court decided was that there was no valid contract, simply because there was no contract capable of meeting the requirements of s2 Law of Property (Miscellaneous Provisions) Act 1989 (ie that all the terms the parties had expressly agreed must be incorporated in one contract, or in each counter-part if contracts are exchanged). In simple terms, there was no contract to enforce (and so any notice to complete was invalid). Note: this was not a situation in which all the terms had been agreed, but those terms had then been wrongly omitted from the contract – if that had been the case, then rectification could have been sought. The problem in this case was simply that there was no meeting of minds, and accordingly no valid contract. Source: Lovells. © Practical Lawyer