Bob - thanks. The question in my other post does seem similar but I hadn't thought of it that way. Your suggestion of pasting a copy of a working partition with appropriate settings appears to be similar to Brian's recipe in his first post above.
Brian - I tried your recipe which kind of worked although I just copied a partition using IFL without using the additional options you gave in your earlier post above so it didn't change the UUID. Still it created a boot directory in the EFI so I could have done it properly. I have created a note with these instructions in case I need them in future. Again many thanks.