Long time since I started this thread. Thought I would provide an update with coding for anyone searching this thread. I used genuine audi parts for an A3 8y - package number 8Y0.054.634A with wiring harness 8Y0.054.733 which cost £232. It came with instructions for fitting but not coding. I put the wiring through the car following the recommended route although short cut down the boot side trim rather than take the whole side trim out but the rest was along the floor clipped to the existing wiring. No trim broken or clips. One change I made was to use the earth inside the boot lid rather than inside the car body as this also saved removing some of the trim. Gaining access to the J533 module for connections was difficult and took some time to release and wriggle out from behind the steering column.
Coding using OBD11 professional
Gateway 19 long coding
Sdf unlock
PaCo_video_parksystem change to RVC_compact_smart
Multimedia Adaption:
Search bap:
VPS_0X0B = activate
VPS_OXB_msg_bus = terminal15
Search function_configuration_unit
RCV_ video_input = Ethernet
Note: If purchasing a new camera as I did from audi you will need to load parameters via e-odis. Any garage with e-odis should be able to do this if you have the audi part numbers. My local independent vag garage charged £50.