They won't like you cancelling the policy because Carcraft will lose a lot of commission, but if there is nothing in the wording to say you can't cancel then they have no right to stop you from doing that, check the wording thoroughly and cancel, or take it to your local Citizens advice for clarification, contracts work both ways after all said and done.
I used to have a policy with Warranty direct and that was good, they have a list of their own associated approved repairers and you take the car or they tow it, and they just charge warranty direct for the repair. The full cost of that policy was £220 / year upfront for a high powered sports coupe. I had the policy for two years and had repairs done totalling £1600. (link below)
http://www.warrantydirect.co.uk/quote_page1.html?wd=1