Alun, I think you mentioned somewhere that you are in Australia?
If you can get a dimension from someone I would be happy to knock one up on the lathe for you?
Postage would be the only cost so if you are in Oz that wouldn't be outrageous.
Thank you for that. I am hoping to get some dimensions soon and will check with local specialty fastener first, as I have been told it is a simple washer.