Turboman
Mab An Gov
I think the best bet it to leave someone in the vehicle and the other person head back down the B855 towards Brough. There's the Windhaven cafe and camping and then further on back inland there are a few farms. Hopefully someone will have a 4x4 for towing a caravan or a farmers will be around.
Quite possible someone with a 4x4 will appear in the car park during the day. Popular spot with sightseers. If he is only 15m from tarmac, and has a decent rope, a car might be able to assist.