Park Distance Control sensor damage?

[godfried]

Hi Guys, I have a bit of a problem and need some help. While reversing I hit a small post and damaged the ''skirt'' where the parking sensors are fitted. I was able to push the dent out but one sensor is pushed-in. I tried to push it back, from behind, but it is not completely flush with the skirt surface. The sensors are factory fitted.

How to remove a sensor?
Car is a 2003 A3 1.9TDI

Thanks for your help.