The reference for pretty much all of the book is the German market. That's where it was born, that's where the desire and taxation regulations for the 5l and 3l cars came from, the AL2 Open End story and the older Audi stories are all important for the backstory of the car, but they're particularly relevant for that market.
I know for a fact that this was fact-checked and cross-read by a bunch of the German forum and there were pre-publishing versions at the meet a couple of years back. There are also some corrections to be done for edition 2, but I'm sure this is a niche-niche-niche market and I suspect that they've sold <500 copies. The (German) forum features towards the end with a list of issues with the car that he put together.
I don't see a market. If there is one, it's smaller than the German one; of the A2s sold, ca. 35% stayed in their home market, I believe.
Realistically, at a book price of at least £125 (remember those publishing rights aren't included in the translation / rebuild calculation), I don't see how many would actually take the opportunity. €40 shipped is rather different.
And please do not underestimate the requirements that Audi would have on this. The name Audi Tradition is on there, and I've seen some of their marketing requirements (for photos) and it would need to be a professional job before they'd accept it.
- Bret