Yeah I did this a few years ago. My mortgage was with Nationwide and I think I was even able to reduce the ammount it was for and increase the length of the mortgage when I moved it to my new property. Was even able to change it from a joint mortgage to being only in my name (had just split up with my ex) Can't really remember how it all worked, I had a mortgage advisor who did all the paperwork and stuff but as far as I can remember it was really straight forward. Sorry not sure if that has been any help to you!