And the winner is ...

... Anthony, who kindly posted a comment with the information that the song (Have I stayed) too long at the fair was written by Billy Barnes.

Many thanks to you, Anthony, a prize (albeit (very) small) will be winging its way to you very soon (or not).

I suppose I should be concerned that I (a librarian with over 30 years (count them) experience) was unable to find the answer but it's mostly done with smoke and mirrors anyway and delegation is a valid research tool. (Well, it is now.)