Any case according to literature connecting a towbar electrics is provided for by the manufacurer in the form of a socket dedicated for the towbar. But where?

According to some very bad diagram https://www.pfjones.co.uk/Wiring_instru ... 050D1U.pdf page 70 shows what I think is a power pick up but where you get the data is a mystory to me.
I do wnat to use the fancy CAN bus as I've got the Ryder smart logic block and I definately do not want to intecept the loom.