Afternoon Rob
I have just read your post and I'm sorry to hear about your numerous problems regarding your Q8. However, it seems from the replies that you have received numerous helpful threads in helping resolve your issues.
For my part, I think you have been unfortunate. I bought a Q8 55 TFSI Sport new in September 2020 and have just completed 28,000 miles just returning from a 3 week driving tour of Deutschland.
In the past 26 months I have had a few minor glitches with the car but nothing approaching the stuff that you have endured. I have had the Audi pre-sense and auto headlight system drop out of service, only for it to come back to life again at the first start up of the car.
Several months ago I had the bottom screen.....the one with the HVAC stuff......just blank out......and then after the next start up, come back on again.
I presume that we owners have to accept that this is a pretty complicated car with alot of electrical gizmos.
So, to sum up , I am very happy with the car and I hope....eventually.....you will be too. We did over 2000 miles in the 3 weeks in Germany, many on unrestricted Autobahns and the car was quite sublime at speeds exceeding 100 mph.
I did note that you reside in Hampshire as do I. Although I used the Audi main dealership that supplied the car ( Swansway Group in Crewe ) for the first 2 services and a decent job they did too. For the cars third service before leaving for Germany I used a Hampshire based VW / Audi independent garage .
I am now an old guy in my 70's and retired. I have been fortunate enough to have an understanding missus who allowed me to indulge in my only true vice.....nice cars. Like you I have owned a fair number of Porches/ VW's and Audis over the years and I have always used this garage to service and maintain them. The owner is a guy called Matt who truly is a car nut and treats ever car there as his own. I have never been anything other than completely satisfied with the work on my car. Then add in the added bonus that Matts rates are a fraction of the ones demanded by Audi dealers.
So, once you are sorted and you fancy having your car looked at by Matt, please just message me and I will only be too happy to give you details of this garage.
Best wishes.
Frank