I didn't have the best experience with Adrian Flux when I cancelled my 330d insurance.
I was pretty much bang on half way through a 12 month policy with them when I sold my 330d. Cancelled the insurance expecting to get half of my policy money back less, say, a £30 admin fee. Of the £550 or so that I paid out, I was expecting around £250.
Oh no - apparently due to their 'underwriter's rules' I was only eligible for a £90 refund! After speaking to a manager, and asking how they could possibly justify the missing £150, they agreed to give me the full pro rata refund of £260ish.
Although I got my way in the end, it was a pretty sneaky trick that they pulled at first. For that reason I'm not going to use them again. I could imagine that forcing a claim through could be a bit of a PITA.