Legal Assistance Policies

Hi  

         Like 99% of people I insure both the car and van fully Comprehensively, The car insurance cover the van third party on tow, and the van insurance the rest.

        Now on each of the policies I have a Legal Assistance Policy (optional) .

My question, would one of these polices cover both vehicles.  i.e  if I cancelled the one on the motor insurance, would the one on the caravan give me assistance if I had an accident in the car, not towing, or the car policy if I needed assistance with a third party claim when pitched?   

Do I need both policies??