I had reason to hire a towcar a couple of years ago.
A local chain 'Afford Rent a Car', told me they had tow vehicles. It turned out to be a large US Ford pick up. When I collected it, despite assurances, I found that the electrics were just single 7 pin, whereas my caravan had 13 pin> So I called in at a nearby Halfords who luckily had a converter lead in stock. It annoyed me at the time because I've not had to use the converter ever since.