Auction sales
57.—(1)  Where goods are put up for sale by auction in lots, each lot is prima facie deemed to be the subject of a separate contract of sale.
(2)  A sale by auction is complete when the auctioneer announces its completion by the fall of the hammer, or in other customary manner; and until the announcement is made any bidder may retract his bid.
(3)  A sale by auction may be notified to be subject to a reserve or upset price, and a right to bid may also be reserved expressly by or on behalf of the seller.
(4)  Where a sale by auction is not notified to be subject to a right to bid by or on behalf of the seller, it is not lawful for the seller to bid himself or to employ any person to bid at the sale, or for the auctioneer knowingly to take any bid from the seller or any such person.
(5)  A sale contravening subsection (4) may be treated as fraudulent by the buyer.
(6)  Where, in respect of a sale by auction, a right to bid is expressly reserved (but not otherwise) the seller or any one person on his behalf may bid at the auction.