Sellers and buyers are expected to suspend the laws of supply and demand; a seller's estate agent is expected to conceal from his client the fact that he has received a higher office for the property; negotiations for a house sale will never get anywhere beyond vacuous waffle in case the buyer commits himself unwittingly to a deal which, for example, he has not financed or the seller commits himself to a sale when he has nowhere else to go. For how long do you suggest that the parties are bound by their "agreement" before one is entitled to call time and sue for breach of contract?
You state that no change in the law is required, but as any law student will tell you, a promise by a seller that he will not increase the price of the property is unenforceable unless the buyer makes some payment in exchange for that promise.
As for the extraordinary proposal that surveyor should be liable to anyone to whom the seller bandies around their survey, this would involve rewriting the law on negligent advice with widespread implications for all professional advisers.
What the Government appears to propose is a preliminary agreement, to be entered into before the usual contract, which will be subject to so many conditions and get-out clauses that it will not be an agreement at all. Like many New Labour initiatives I doubt very much that we will hear much more of these proposals.