Richard, seriously I would leave it, the trim is a bloody ridiculous design, probably one of the mistakes that was left to the fresh faced young designer to come up with.
I wanted to replace the panel as the grab handle had somehow snapped off (?!) I spent the £54 for the panel from audi, all the bits are there including the release cable.
However it relies on sprung clips, no screws, than need to prised off and sound like you have broken something when you do it, and then need to be whacked into place, and I mean whacked into place, to get the panel to stay on.
The job requires the dexterity of an octopus or at least 2 people to do properly keeping the cable attached and pressing the panel in place etc etc(it took me hours on my own!) and the likelihood of you bending the flimsy aluminium panel slots for the clips to locate in is extermely high.
Get the lock replaced at Audi and anything else that needs oing under there cos when you have had it done once don't go there again!
Cheers
Glen