Interesting read. As we know, Brexit isn't happening so this probably will apply to the UK too. I guess this will apply to the new A3 but probably in its future FL guise and not the one due to come out.
https://www.theweek.co.uk/93687/eu-lists-11-car-safety-systems-to-become-mandatory-from-2021
https://www.theweek.co.uk/93687/eu-lists-11-car-safety-systems-to-become-mandatory-from-2021