Ask these guys about reversing cameras:- https://audi-retrofits.co.uk/
Good luck with your purchase. Hope you can drive a hard bargain, so you get all the features that you want. Is it a private sale or Dealer? Independent inspection is a must for any used car, especially when spending that much money! Do some homework on common issues, how much it might cost for those repairs, and drive the price down, down, down!
This site is very handy for reviews, recalls & common faults:-
http://australiancar.reviews/