I had to take the rear drivers door panel off as I ordered the S puddles lights and wanted them in the front and the standard Audi Rings at the back, but the S lights didn't come in so at PDI they fitted the rings to the front and sent me the S ones.
When I took the standard rear light out, the clip snapped off (wasn't an issue as not using them) but it somehow fired up the door card and I couldn't get it, not surprisingly as it had gone right to the bottom corner where the door card clip has a an empty space behind it (no idea how it got there)
Fortunately my friend is a Mastertech so helped me take it off - One screw is obvious under the arm rest but there is another behind the speaker grill under the arm rest (Not the speaker at the bottom) which is really tight and he did say they often snap (well have on other cars first 8Y he'd worked on) so be careful - You need a small prying tool and a bit of bravery. After that trim removal tools to get the bottom clips out and it will lift off, remember the multiplugs and door handle system are still connected.
It's extremely tight and there's a good chance it will break I'm afraid - Real trial and error to get a small screwdriver or plastic prying tool that you push between the door card and the top of the grill until you find a clip - Careful the screwdriver doesn't slip as it will scratch the door card
Sorry can't be much more help than that but you have to be brave and prepared that it may break