In reply to gavinpeach:
I went down a full Euro size verses my high street shoe size. The shoes are very stiff in the sole so you don't need a desperately tight fit for good edging. The main thing is making sure the heels won't slip in whatever size you go for. Because the soles are so stiff the heels will leverage off when edging if the fitting is too loose. I've used my pair intensely outdoors for nearly a year and haven't noticed any significant slackening in the fit.