So my 64 plate A6 ultra has had inspection service and Adlue top up. One day later, Adblue warning message, no restart in 600 miles. Back to the Audi dealer, oh yeah, this is an issue with some of the 1St Ultras, so they change the Adblue sensor, doesn't clear it, I am now without the car for the weekend because they are now going to replace the Adblue pump!!
Hope this solves it, anyone else experienced similar??

At least they've given me a lovely A4 s line quattro for the weekend!!