Thanks guys. Yes, sadly didn't think about checking online reviews before buying at the show. I paid by debit card, but NatWest have been really helpful in the past so I will get in touch with them next week.
One thing to add though, is that I'm going to Silverstone MotoGP on Friday next week. They seem to 'do' quite a bit of motogp stuff, so could be they're there. If so, I'll be coming home with 3 canvas works from them on the day I think (I know people were taking them away with them at beaulieu).