I know you're in the UK, Diz, so I don't know if they offer it outside of the US site, but lands end has a pretty nice feature where you basically take your measurements, enter them into a little app on their web site and it builds a virtual model for you so you can "try on" stuff. We did this for my daughter who is a tough fit and it recommended a size for us and all. It was a little spooky how much the model looked like her, too. When it came in the mail, the suit fit perfectly.