Thanks Jerry.

The other point that might be worth mentioning is that in UK copyright civil law, at least, the word 'folk' has no meaning whatsoever. Whereas the word 'trad' does. It's not quite the famous '54' definition, but it does mean 'in the pubic domain.' That's a useful distinction, and one that both writers and singers should note.

When I listen to my old recordings I'm amazed by the amount of change that's taken place in my own interpretation of my own songs over time. And as for the 'subconscious plagiarism' thing - it helps to have an expert musical partner who can identify even a two-note reference. (but we just sang em anyway)!