On the AdBlue topic, you can get the no restart message flashed out of the ECU at a fraction of the cost of replacement parts. Give Andy at https://ecuflash.co a call.
On the wider get rid or keep topic, I’ll never buy another Audi again. 16 plate B9 (actually B8.5 according to it’s car plate). Owned for 5ish years and I’ve put 50k on it. 80k in total.
I’ve spent about 7k keeping it on the road, fixing issues that shouldn’t be there for a car this age and mileage. Not including “on-the-road costs” like tyres.
-Had the brake servo/abs issue.
-Had the AdBlue issue.
-Odometer failed and had to be replaced.
-2 broken rear coil springs.
-Have the issue with low interior heat.
-5 (yes five) new sets of front discs/pads due to excessive warping.
-1 new calliper.
I can go on, but suffice to say my experience of “Vorsprung durch Technik” is actually “our technology is crap”.