Bob Engelhardt wrote:
... I've asked on the Practical Machinist forum. If I don't get
an answer, I'll try Bottomly. ...

I just got the reply on P-M:
"I have spoken to Alan about the hinges and he has brought a box of the
prototype hinges into work today. I think he will write a bit of a story
about the Magnabend development over the next week or so. Geoff is away
on holiday at the moment (far southwest of Tasmania) where there is no
technology, but when he gets back I will see if he want to add something."

Bob