Well Gents, once again I was wrong. I must have misunderstood Tony.
Thanks again Geraint for your pointer to the standard docs, but I have no trouble with the standard repeating events, even the strange ones. I do always look through the documents prior to asking my questions.
Tony, I think that I need a create that does actually create "n" unique records/rows each year. (Sorry for the dated references but they have been records and fields to me for some 40 years. I will catch on eventually).
A check box on the create event that says that it will add "n" unique rows will do. But as I need to edit each event anyway, the copy and edit is really close to what my current process is like. If it would pre-fill in with the next third Thursday of the month would be another way to get me through this hoop. You already have the repeating algorithm worked out. I will try to create a few events with the Copy and Edit button. If the copy brings the Thursday rather than date number, I am there.