I just did a video showing how to remove/refit the electric adjuster on the S3 facelift headlight unit.
It's the same for the A3 halogens I believe - dunno if it applies to other models.
Show's how to do it with the light unit sitting on your lap but it's just as easy to do with it in the car.
I really just wanted to show how simple it is to do without any force or damage to the clips.
Hope this helps someone.