Mystery part

Removed the drivers door card, and found this floating around the bottom of the door. Is it a MG part? If so what does it do and where does it fit? I've looked on parts diagrams but not seen anything similar.

It is the window stop. I just put new ones in my '96 F to sort out the windows which were always pushing up into the hood and the rubber seals around the windscreen. The 2 I found in the bottom of the doors were white which were the original parts yours looks like a picture of an update I saw. New updated replacements can be sourced from several places on the internet - can't remember where mine came from, Possibly MGspares on ebay as I have had a few bits from them.

Roger