The auctioneer states 'passed' if the item has not reached 10% of reserve, or if the bid is within 10% but not completed by the end of the auction period. It does not mean it is not sold, as negotiation might still be taking place. Subsequent results therefore can differ from just listening to the auctioneer. I doubt the Heinkel bid being accepted, but the BMW 600 must be close to the reserve, I would think. It might yet be sold. After all it is in the auctioneers interest to complete as many sales as possible, as well as getting the highest price as possible. If your choosing an auctioneer you are going to select the one with the best record as a contender. Equally the auctioneer is not going to except lots with reserves set to high, as he needs to have a reasonable chance to sell them. People who believe they can get Christies to sell a Peel on a £100k reserve, think again. They might achieve the price, but will only take the commission on a much lower reserve.
It is not uncommon for eBey adds to be taken out, and classified adverts placed, for cars in a specialised auction. Its simple and effective advertising. But you still need to register to bid, including any costs of publications or services required to gain a bidding number. such is modern coms that some auction offer a live feed to none registered bidders so they can watch the proceedings. I assume the hope is you will get excited and register to participate at the last moment. By pre advertising the cars, the Auction house has shown due diligence in describing the item for sale. Buyer beware.
I am surprised you do not know all this, Steve. Unless you never frequent auctions. I confess I am no great fan of buying, or selling in auction. Its often hard to get a true understanding of the items for sale. I therefore adjust my bid to take in the risk element of a lack of information. Generally, therefore, there is someone who will bid believing all the hype, and I will waste my time. The advent of expensive catalogues just stops me dead in my tracks. I am not paying to attend an event where I have minimal control over the process. So I chiefly attend junk auctions. These have a tendancy for all sorts of tricks, like' bidding off the wall'. All the easier with mobile 'phones. So you need to have your wits about you. There are bargains to be had though. Its a game, like any other. I am much better at autojumbles.
Others have reported the Tourette previously sold at a hammer price of £15,000. I do not know what the premium was, so I can neither confirm the hammer price, nor the paid price. But given the short period of ownership, a nice little tickle whatever it was. As I think last time the car was, as mentioned above, a bargain. Just compare Brooklands results with Blenhiem's a few years ago, where the Tourette last sold. Prices have resin a bit, but Brooklands stands as a better set of results, as does the sell off up at King Lynn last year. The vagaries of auctions.