Together we are strong!!!
I did the following because I still had a backup of the settings:
a) Opened my backup and copied the contents of the file for my yoke (I think without changing the header in the first 4 lines).
b) Copied into the last file created by the system (with the missing assignments) and saved.
This left the varying folder and file names that MSFS itself had created unchanged.
Worked. Got my painstakingly created with sometimes up to 4 mappings per key back.
Thanks for your support.