Initially I approached the Factory but due to complications regarding the export of stock oversees, and the fact I discovered that I had Rob's jig for the job, I decided that it would be just as easy to make a new set. The jig, in two parts forms the basic shape of the hinge and allows the mounting and pivit holes to be drilled and reemed.
The basic set of six hinges took a weekend to make using the jig and some 0.050" 4130 steel sheet.
1) Six oversize blanks were cut from the sheet steel. The size is sufficient that each piece fits snuggly in the jig ready for pressing.
2) The basic shape is pressed using a vice.
3) While still in the jig, the mounting and pivit holes are drilled and reamed.
4) The blanks are roughly shaped (original hinge shown for comparrison).
5) Final finishing with file and wet/dry paper and comparrison with an original hinge.
6) The final modification is to spot weld a tab onto the hinge to provide a flat. Each clevis pin will have a flat filed to fit thus preventing the pin from turning against the hinge.
Lastly, my thanks must go to Rob Lees and David Nowill, who between them, designed and manufactored the jig, and then let me use it.