My inner left parking sensor has dropped into the bumper. Is there any way to reach it without the rear of the car being taken apart?

 

If you remove the screws at the rear/base that clip it up to the underframe of the car you should be able to get enough flex to get a hand in there without taking the whole cover off. I did it to remove an annoying stone that was rattling around and survived with only a few scraped knuckles.

 

Thanks Dave. I'll give it a try at the weekend.