UPDATE:
I took it to the stealer after they assured me they said they knew what to do. However after pissing around for 2 hours, it turns out that they, "couldn't get into the ultrasonics part of the alarm". In other words, the whole reason for going was so they could turn down the ultrasonic sensors, but they didn't know how.
In fairness they did say that there could be a fault and are sending the results to VW.
But if there is a fault, it isn't coming up on the diagnostics system!
So I'm back to square one.