For those who are interested I have just fitted a Westfalia fixed swan neck towbar to my type S GT, no problems at all, only neede to trim a small peice of the rear bumper to get it to fit. the Westfalia model number is 338064. Electrics were model specific, and apart from having to dismantle most of the drivers side trim to connect everything, worked first time. Also fitted a set of CISBO rear parking sensors whilst the bumper was off, seemed like a sensible thing to do at the same time. Apart from a dodgy wire connection on the power connector which I had to fix, they seem to work well. I'll post a pic or two when it's abit cleaner .