Looks like a gear tray from an old fitting maybe? Looks mint though bet it would last donkeys years!

Nice restoration I also love old gear trays like this I wonder if it's out of something along the lines of a Thorn format style fitting

Yes it looks similar to the gear tray on the BC fitting with Opal diffuser from Lampy, elsewhere in the gallery, which is what prompted me to upload it. It was supplied with a BC plug on very badly deteriorated rubber flex and was really dusty, almost as if someone had emptied a hoover bag over it.

Interesting piece, I wonder if this is designed to go into something else?

Looks simular to the sort of thing I used to make when I was messing around in the garage many years ago.. I recon a couple of suspension hooks and off you go