These were purchased to replace a previously excellent Waterflex model. Unfortunately the website didn’t describe the actual size of the shoe in uk/eu numerical, but rather Med, Large, extra large. I went for the extra large as these are quite tight normally and owned a 46 previously. Unfortunately after removing the packaging these are way too large - worth changing the size description on the website.
Sorry to hear that you've had a problem with the sizing. If you email email@example.com we can get it sorted for you.
You were definitely right about the product size and description not being up to scratch. I've just modified the page so that the size drop-down includes the UK size, and I've also added a size guide table in the main description, so hopefully nobody else has the same problem you did.