Lost a cover - any idea where I can get a replacement

Hi

I am really careless and have managed to lose the plastic screw cover for the 10-pin remote adapter terminal on the front of the camera.

Any ideas where I can get a replacement from please.

Wouldn't it be a great idea if you could buy a pack of all the likely spares that somehow get lost like eye-piece, LCD cover, and the various rubber/plastic seals....

Thanks

Rick