I was a little confused as to what size, as like you I'm a comfortable size 10 (apparently 27 on here), but I can get into a size 8 in some jeans! I had no idea which size to pick, and whether a 10 would do, or to try a 12? In the end I've gone for the 12 and they fit okay on the leg, but a bit big round the waist! Although annoying a size smaller wouldn't have fit at all!
Thank you for clarifying this!