I have always thought that a size 7 is a 40. I have worn size 7 shoes in a 40 and they fit okay. However, I was given a pair of size 7s a few months ago which I thought would be okay. They are far too big and are actually a 41. I tried wearing them with insoles and two pairs of socks to pad them out, still too large. So why is it labelled as a 7, if it is a 41? And what size is a 40 in the UK?