£500 is exactly half the sum I was quoted by Marshalls in Cambridge for fitting the tow bar to my Freelander so onto Ebay and bought a genuine towbar for £75 this included the genuine electrics. Removed the rear bumper (took about 30 mins) installed the towbar (about 1 hours work) and cut the bumper and replaced it.
It then went to Marshalls for a reprogramme (cost £57)

Now works perfectly

couldn't get a price on the reprogramming so I'll have to wait until monday Too many cars, too little time