^ I would have thought it's easy enough to figure out if a merchant is trustworthy or not (and if it's not easy, then I dont trust them). I think if you're not going to trust other sources (outside Europe), you're going to need to buy from someone in the UK -- you may not get the best possible offer, but you have more protection if something goes wrong.
Me (in .de land), I think I'd prefer to buy from one of those Chinese sites mentioned than from e.g. an unknown supplier in a different European country.