I'm usually a U.K. Size 5, so ordered a 5.5 - as all of my other Uggs have been fine with a slightly bigger than normal size. However, due to the pointed toe, I found that there was not enough room. Sole Trader were brilliant - I rang our nearest outlet store, they reserved a 6.5 for me to try. The larger size was perfect, the store then returned the original ones and within a few hours I got an email to confirm my refund.
The boots are very comfortable, good quality (as usual) and look great dressed up or down. Would highly recommend.