But if the insurance company works pro rata then you will get all of the money back you are owed rather than a percentage as Andrew stated above.
i.e £600 policy which you cancel with 2 months remaining means you will get £100 back (£50 per month)
Find a company who works on a pro rata basis pay the policy in full on a 10mths 0% interest credit card and pay it off when you cancel your insurance

When i sold a motorbike and cancelled my insurance the insurance company paid me the remainig 137 days or what ever it was back by working it out pro rata. Halfax insurance used to work pro rata but not sure if they do now?