I'm trying to save time and buy a pair online. I'm a size 5 UK, should I get a pair in size 4 - 4.5 as I understand they are bigger than standard shoes. I've bought a pair before but I can't remember what size I bought them in and I've lost them to check. . Anyone a Birkie expert. Or should I just take a trip out to a stockist and try them on? (I'd rather not though)