Quite a significant amount then. On one hand you could argue that if he didn't have the offer he wouldn't have had the temptation, don't get me wrong he should have honoured the selling price or used a reserve/buy now etc but if somebody had emailed him saying ill give you £1500 more if you sell to me instead it gives him something to think on. If they had just said I'll buy it if it falls through he'd have had no incentive to even contemplate pulling out.
The other "buyer" could have placed his bid to win it fair and square in the first place ? Just shows its a tough old world!
In this situation I have emailed sellers of boats that went before I spotted them but I only offer the same price should it fall through so there's no temptation for them to start some kind of Dutch auction. I have offered to pay £50 just to get first refusal if the buyer pulls out but I'd not offer more to break the original commitment. If the original buyer takes it I lose my £50, chance I take.
Still it worked out in the end for you. Why not sell it to the other guy for the £1,500 more he originally offered
Peter @ Boatsandoutboards4sale ~ firstname.lastname@example.org
~ 07930 421007