Tried calling the local VW dealer who supplied the kit. They promised to get back to me but no news yet. All the other wiring kits I looked at show earth connecting under passenger seat.
Only thing I can see to attach anything to within reach of the cable length from tow bar is the bolt hole for one of the bolts that holds the spare wheel tray up (see image). However, I've only ever seen male lugs for earth's and it doesn't seem a good idea to have a plastic tray pressing the earth wire ring onto the body.
Only thing I can see to attach anything to within reach of the cable length from tow bar is the bolt hole for one of the bolts that holds the spare wheel tray up (see image). However, I've only ever seen male lugs for earth's and it doesn't seem a good idea to have a plastic tray pressing the earth wire ring onto the body.