Righty oh. Better later than never.
I have, with the help of a mate who can fly Fusion 360 much better then I (I can't) come up with a design for these from Williamson's measurements, and printed two out. They are bright orange because that is what was in the printer, but I can change that to black, white, red, blue, or grey if required.
Who wants to be the tester for me? Williamson? StormST? Someone else?
Pm me an address and I will post a couple out.