You are going to have to look at the small-print on your contract with the estate agent. What exactly does it say about payment for the HIP report in the event of you withdrawing the house from the sale. Whatever it says is what you are going to have to pay. If it says nothing, you owe them nothing. if it says you will pay the fees incurred in preparing the report, then ask for a details breakdown, but I don't hold out much hope for you reducing this figure because it is extremely easy for a �500 invoice to be produced. Unfortunately the moral of the story is one has to agree up front the exact figure, or at least a cap, or you are likely to get shafted. You could try local Trading Stds, but I don't think they will be able to help - it doesn't sound like an unfair contract term to me. Give us more relevant details about what the contract says, please.