Well
www.ecutesting.com were not a great help after all. The wanted a part number for the mechatronic unit before they could tell me anything. I found a part number... they did not recognise it. Surely if i just tell them i have an 07 ED30 they would know if they could repair it!? I wasnt even asking for prices at this stage, just whether it could be done.
If i dont have any joy from the VW warranty route, i am just going to hunt down a new unit and fit the bugger myself.