Thank you. That's rather helped put my mind at ease, as hearing your situation doubly confirmed that what's been diagnosed is the issue (and not a coincidental additional fault found during the diagnostics). We were travelling on a quiet road, with kids and dog, and able to stop immediately and evacuate as we really did think it was going to go up in smoke. You describe it perfectly. As for VW dealerships..... It was recovered to my local one, who said they could not even look to diagnose it for 2 to 3 weeks, and with a holiday in 10 days, I had it moved to a local electronics garage, family business, which, understanding our predicament, looked at it the evening of it's first day there, and diagnosed it, and fingers crossed we get it back Wednesday /Thursday, good to go, as soon as the part is delivered. Thanks for taking the time to comment on my post and, as I said, help put my mind at ease.