I do not know what happened with Gene's bid at Gavin's but the system works pretty much the same at most UK auction houses, sealed bid and timed auctions being the exceptions.
My clients and I bid quite a bit on UK auctions and for the most part are pleased with the results. YMMV but shrewd shoppers still do well playing the game. One of my clients, a board member here, continually shocks me with his buys. He has a variety of tastes and picks out quality others overlook, he has done very well at Holt's.