Hi there. Breakdown advice needed please

Hello there. We have been caravanning for many years, but are going on quite a long (UK) journey. OH wants to get breakdown cover for the caravan but the problem is this: We have a Motability car and it is covered through Motability by the RAC. If the car breaks down then we can only use the RAC, but they do not cover the caravan. Does anyone know of any breakdown cover just for the caravan? If we go with Mayday, which is the best level of cover for our situation? Is it worth going for the middle cover bearing in mind the car will be sorted anyway.

Many thanks.