Nice idea. I'll look into V1 and V2 images. The only thing that it resembles is from a Sunderland flying boat but they would have been imperial size nuts and these I'm sure are metric.
Was maybe half inch thick. Single black cable. 2 or 3 wires inside with coloured sheaths as far as I remember.
No it's all aluminium. A few stainless nuts and looks like a small stainless plate under the 'engine mount'
I found this on Brighton Beach after a storm years ago. Size is about 1m (41") square. It had black, rubber-sheathed wiring running the length which has deteriorated.
I put callipers on one of the stainless nuts and it's metric so I suspect German (but could be a weird imperial size). Shot down...