Guys,
With the information provided by Rick Cove and the aid of some sketches from the operators manual I had enough information to take to my local engraver and have a new one fabricated. These small items can be just as rewarding as the larger components.
I cannot begin to think how difficult this process would have been without MLU and it's members. I quite like Phil Waterman's words on the subject of "paying it forward".
Peter