Thanks for the info all- obviously disappointing to hear. Not sure about the paintwork; there are some 531 stickers on the forks but I doubt this is the place they would be and given that there is a Colstar sticker on there it doesn't really mean anything :/
That said, the frame does feel pretty light (haven't been able to weigh it) and the bike rides well.
That said, the frame does feel pretty light (haven't been able to weigh it) and the bike rides well.