Rear door rattle advice?

[Basil]

Been having a rear door rattle for a bit now. Finally decided not to stop being lazy and get to grips with it. Turning the stereo up worked wonders for a bit....

The rear has electric windows - the rattle sounds like it's coming from somewhere around the lock mechanism area.

Any tips/comments on what it could be before I get medieval with its a**?

I hasten to add that I've removed the rear seats....

Cheers

Bas

[bobjim]

big hammer, or expanding foam to fill each cavity