James, I've just tinted my rear door windows on my avant as this is how the rear door cards come off:
Remove door trim strip and remove the screws behind it (as above).
Remove screw in hole under arm rest/handle. It's a phillips and it can be a pain to locate, just keep the screwdriver as horizontal as you can as you insert it in the hole in the armrest and you should find it eventually.
If you have rear window winders instead of electrics (so doesnt apply to you James) you need to slide the top cover off the winder (dont try prising it off) then undo the screw beneath the cover. The winder handle will then pull off the shaft, note there is a black plastic washer there too that needs retrieving.
The next bit involves squeezing your fingers under and behind the bottom of the door card to be able to pull it sharply towards you. If you cant get your fingers in far enough then try and get them behind the door card each side about a third of the way up (you may need to work your way up from the bottom) and stretch the door card outwards, this will pull out the locating tabs at the side of the door car and allow you to get your fingers futher behind it to get a better hand hold. When you can get a good hand hold, pull the bottom of the door card towards you sharply, there's one of those black clips at the bottom that will either come out or more likely snap off (hence the need for replacements). The bottom should now be loose.
Now working your way up the door card snap off/pull out the remaining clips at the top (think its 2 each side) plus there are 2 white plastic smaller clips, these are located at the top of the door card (about an inch down) and are at each end of the door card.
When all the clips are out its a case of wiggling the rest of the top of the door card from the window seal. Then when its off, disconnect the door handle pull wire and wiring loom.
Replacement is reverse of removal. You will need to replace anywhere up to all five of the black clips and maybe one or two of the white ones too so get spares. I've not removed one yet without breaking at least a couple of black ones and the odd white one.
Also, make sure you remember to reconnect the loom and handle pull wire, and locate the tabs on the sides of the door card before bashing the door card back on the door otherwise you have to take it off again and replace yet more clips!!
Black clips are 8E0 868 243 (5 I think per rear door)
White clips are 8E0 867 276 (2 per rear door)