I had to replace the 14 pin plug and that was very fiddly to do. Replacing the entire lead means working under the A frame and them into the van to the main panel ( where the fuses are ) even more fiddly.
If the cable is just abraided and not cut through I would carefully peel back the outer sheath, seperate each of the wires and wrap separately each of the damaged wires with pvc electrical tape and then bind all together with more pvc tape.
Thanks, should also have mentioned that the car was letting us know, every time OH put his foot down, the horn sounded. do you know if your idea would stop that? I suppose we could try and see what happens.
Any caravan shop will stock the cable & the plug. You need to measure how much cable you need. Probably about 3metres. Then you need the ability & tools to put it all together.
If you don’t have that knowledge then get a caravan workshop to do it.