Auction sales 72 In the case of a sale by auction the following rules apply:
(a)if goods are put up for sale by auction in lots, each lot is, unless there is evidence to the contrary, deemed to be the subject of a separate contract of sale;
(b)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 that announcement is made a bid may be retracted;
(c)if a sale by auction is not notified to be subject to a right to bid on behalf of the seller, it is not lawful for the seller to bid 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, and any sale contravening this rule may be treated as fraudulent by the buyer;
(d)a sale by auction may be notified to be subject to a reserved or upset price, and a right to bid may also be reserved expressly by or on behalf of the seller, and if a right to bid is expressly reserved, but not otherwise, the seller or any one person on the seller's behalf may bid at the auction.