Website has uk size 7.5, and 8.5, and I'm normally a uk 8. From reading up on the matter (rock n roll Sunday!) I think they give, so should be getting the 7.5 but thought I'd pick some brains here before ordering.
They are really wide. If you can, order two pairs in different sizes and return the ones that don't suit you. I'm normally an 8 and don't have narrow feet, ordered 8.5 just before holiday and they were too big for me (I kept them because there was no time to return them and I really needed some flat sandals. Loved them and wore them anyway that summer but I know I'd have enjoyed them more if they were a better fit. Planning to buy another smaller pair this year but going to try them on in a shop first)