I was thinking of doing this in the Avant so I don't have to mess about with the dog guard and lay the seats down when I go fishing.
I did this on my saloon B6 but must be the same in B7
Rear seat back out and boot trim off to see the panel that is marked out already to cut out. Once out I had fitted an A6 ski hatch, but then ordered the A4 interior trim panel for a better finish.....A6 one would have been fine if my OCD had not taken over