Car has been returned, LOTS of parts replaced, all related to the valve body. Turns out the service tech forgot to replace one item and the car threw up the fault again. Took the car for a drive on Sunday and all seems back to normal. One note is the PDK seems to hold 6th gear instead of going straight to 7th (in normal mode). I think someone had mentioned that when they got their mechatronic replaced, they PDK has to relearn your driving style. I can confirm that!