Besides Buenchico’s suggestion; most insurance companies will allow you to cancel the insurance cover at anytime - they will then refund your premium for the complete months remaining on the policy, less an administration fee.
Last time I had reason to do this, Direct-line had an administrative fee of £26.
Before signing up for this option, make sure you know how much money you will pay in total and how much you will get back, the difference being the cost of one months insurance.