I meant to reply back to this sooner...
I got a bottle of this Gummi Pfledge stuff about 2 weeks ago and since I applied it, I've been rattle free! My doors are as quiet as a mouse, no more creaking over the bumps, it feels like a new car again - all for 10 euro and no dreaded visit to a stealer

Massive thanks to 182_blue for this extremely helpful suggestion