Well he started it at £10k, so for the seller anything more is a bonus - that's Ebay for you. It's not him that asking £12k for it, it is uninformed bidders pushing the price up. Whether the eventual winner actually turns up and pays for it is another matter....
I think, conservatively he's paid £6500 at May's exchange rates, up to £1500 shipping (worst case), about £400 in tax, £130+ in Ebay fees, add collection costs and time it's hardly a great money making scheme
£10-£12K is a fair price for the right buyer who wants to do a car up their way, given current prices, and current exchange rates. Anything much more and it's a bit of gamble I think.
Also it would appear it's a manual too, despite the listing saying it's an auto.