Having previously fitted tow bars to the last 10 cars I've owned I never encountered much problem in splicing into the existing wiring.
Now having fitted a 2nd hand b max towbar I read splicing may result in damage to the vehicle electronically.
Researching the available purpose made wiring kits it appears to be quite (relatively) complicated.
The so called (universal) alternative kits seem to be a possible solution.
Obviously I wouldn't risk damaging the electronics so would welcome advice on this subject.
Much obliged hywel, was enquiring if anyone had success with an "universal" kit as the proper Ford kit looks very complicated with instalation of extra wiring, running cables etc. I appreciate the on board computer monitors everything but all I needed was a simple trailer board.