If I'm towing a caravan / trailer, does my RAC Breakdown Assistance cover both the car and the caravan/trailer?

Your caravan/trailer will have exactly the same breakdown cover as your car when it's being towed, as long as it conforms to the relevant car's construction and use regulations, it's no more than 7 meters long (with load) and/or 3 meters high (with load), weighs no more than 3,500kg when loaded and weighs no more when loaded than the kerb weight of the car.