I had a Cahoot loan that I paid off in full last month and was in the same situation that you are in now. It was a flexible loan for £6000 and it started off in 2002 at an APR of 6.9%, however by the time it was cleared last November the APR was 14.9%. In short, Cahoot are allowed to change the APR without warning (they emailed me to let me know the APR was increasing on about 4 occasions, much to my dismay). I suggest you pay it off as quickly as you are financially able to.