Thanks for that. The BMW forum seems active, but the Audi one not so much (most users online at any given time was 11

). I did register on Audi World though, but they seem mostly centered on the NA market, so there is very little info out there on the TDI models.
I think my heart is set on the Audi, if I am being honest with myself. I did consider the other competition as well - Volvo, Mercedes-Benz, and so on, but from what I have heard, DIY repair is quite tough on these due to limited access to coding tools and diagnostic equipment. This could be bollocks, but I am just repeating what I have found online.
Audi has the most 'support' in terms of forums/message boards and the parts aren't too expensive, as many parts are shared across the other VW brands. I would even look at the B6 models too, but they are so closely priced to the B7/B7.5 models that they aren't really in the crosshairs at the moment. Their interiors also didn't age as well either, and coming from a 2011 car, I would balk at the thought of sacrificing niceties such as climate control, heated mirrors, electrochromatic rear view mirrors, USB and Aux inputs. I think the B7 strikes a nice balance between a classy interior that's older, but not dated and still has enough features that I won't have to take a step back in this regard.
I'm keeping an eye on the local markets - Gumtree, Facebook, WeBuyCars, Autotrader etc. for any solid deals, but I am not trying to rush into anything and I will do some more research in the meantime. There is an A4 Avant 3.0 TDI Quattro in my area going for a smidge over R100k, but I believe the engine is due for a timing chain inspection in 10'000km or so, and I believe that is not a job for the faint of heart as the engine needs to be removed for it to happen. It had a solar sunroof though, which I thought was cool
Link to the Quattro mentioned above, for anyone who wanted to see:
https://www.gumtree.co.za/a-cars-ba...avant-3-0-tdi-a4-b7/1009990792680910010006209