The Buyer shall forthwith or as soon as possible after the sale, (a) supply his name and address, (b) supply, if so required, bank or other suitable references, (c) pay the full purchase price in a way acceptable to the Auctioneer, notwithstanding any prior arrangement for advance payment required by the Auctioneer, and (d) on proof of payment clear the lots purchased by the times specified. Lots may not be cleared during the sale except by permission of the Auctioneer.