If you are the successful bidder at the auction you will be bound under contract on the fall of the auctioneer's hammer. You will need to pay a deposit on the day of the auction (usually 10% of  the sale price), sign the Sale Memorandum and ensure funds are in place to complete the sale 20 working days after the auction. There is also a fixed Buyer's Contract Fee of £500 plus VAT . If you are not the successful bidder this fee is not payable.