85 In the present case, the matters principally relied upon by the plaintiff in support of its plea were the conversations between Mr Weir and Mr Evans concerning the restraint clause. Once the original offer was accepted, then it follows from the authorities I have cited, putting the issue of promissory estoppel to one side for the moment, that the written contract should be regarded as the sole point of reference in regard to the bargain made by the parties. The vendor of the property sold, on my earlier finding, was the company, K9 Pty Ltd, and condition 4 of the contract contemplated that any personal obligation undertaken by the directors was to be imposed by a deed of restraint. A collateral contract whereby one of the directors, Mr Weir, purported to assume a personal liability in consideration of the purchaser entering into the written contract might, arguably, not be thought to be consistent with the terms of the written contract, for, as in Hoyts v Spencer (supra) and Jutland Nominees Pty Ltd v Nelson (supra), it might seem that the collateral contract went beyond the terms of the main contract. On that view of the matter, the verbal collateral contract might be thought to vary or to purport to modify the effect of condition 4 concerning the deed, and thus be inconsistent. It is apparent from the narrative, however, and from my earlier findings, that, at a later stage, the terms of the written contract were varied, in writing, by Mr Archer, acting on behalf of K9 Pty Ltd. This meant that the contract in its final written form was consistent with the arrangements made by Mr Weir in the earlier telephone conversation as I have found them to be, namely, that the trade restraint clause was not to apply to the Whitford liquor store by express agreement or to the Ballajura Tavern, as the latter premises did not lie within the prescribed radius. Thus, if the parties had proceeded to prepare and execute a deed of restraint before settlement, then such a deed, to be consistent with the written contract in its final form, would have had to exclude the Whitford liquor store. It follows that the personal representation made by Mr Weir in the earlier telephone conversation proved to be entirely consistent with the written contract in its final form, and therefore, in the circumstances of the present case, the collateral contract contended for conforms to the principles reflected in the decided cases.