I have a great deal of sympathy for Steve, he wanted to purchase an all matching numbers Vincent, and probably parted with a great deal money in his quest, but has ended up with a bitsa, but who is to blame for this malady, my understanding is that the spares club are simply brokers in these transactions, for a fee it saves the actual seller having to deal with time wasters and tyre kickers, and also garage snoopers.
Steve was probably under the impression that by purchasing from the well respected Vincent Owners Spares Club that he would avoid all these potential problems, but I doubt that any of the bikes that get sold through the spares company come with any sort of guarantee whatsoever, and how could they. I think there could be a few lessons learnt from Steve's rather sour experience, no matter where you are purchasing your bike from it is always advisable to seek advice from the machine registrar first, it is one of the reasons he is there. Perhaps the spares company could offer a returnable holding deposit scheme, but only returnable if the bike proves not to be kosher when researched, that should remove the urgency from the transaction, and urgency can provoke risk. If Steve had purchased this bike from a dealer, and the dealer had told Steve it was a genuine all matching number bike, then he would have full and legal entitlement to a refund, if that was not forthcoming he could pursue it through the courts (as Jim Gleave, late of Atlantic Motorcycles found out at huge cost to himself, he refused to give a refund on an incorrectly described bike, not a Vincent, and it pretty much cost him his retirement fund, or so he told me)
I think it would be a great idea if all the bikes that get sold by using the Spares Club as a broker at least come with a provenance check from the club machine registrar, of course no mechanical guarantee whatsoever could be offered, the buyer will always have to satisfy himself on that issue.