Update- Just got back from JCT600 Wakefield ( who've been brilliant ) and I now have a working powered tailgate. A replacement control module was fitted and VW customer services have paid 80/20 split. Their reasoning, " frequent use of VW Van centres" or in my words, a full VW service history. The fact that the fault had previously reported probably helped has well, has did my many calls to them, each time a different agent, each time ( though I had a case number ) I would have to give the full tale again, and each time the first response was no. After several attempts, I tracked down a senior agent who seemed to take a bit more interest it my case , and went away and came back with a positive result. VWCS are a typical offshore call centre, with all the problems of a noisy call centre, heavily accented operators and a knee jerk reaction to say no to everything, but my persistence finally won out.
A positive result, that has gone a small way to restore my faith in the brand, but this is my last Transporter.