I understand I can return my watch if I'm not happy with it. I thought it was 30 days but looks like it might be 14 in the UK. Anyway, what is the policy if I want to exchange it rather than return it? I got the 38mm on Sat and it feels like its too small, can barely type in my passcode without hitting the wrong numbers. Do I have to pretend I just want to return the 38mm, get a refund and then buy the 42mm from scratch or can I actually go into the store tell them I got the wrong size and I want the 42mm and they'll happily exchange it and charge me the difference etc?