Both Malcolm and Rick are correct, of course, but in those days so many people were just finding out about trad songs and cross borrowing was rife. I'd like to add that Martin IS an honourable guy: e.g. In and around 1964 I sold Martin a piper's knife for £1 as I was broke. A few months ago I met him at Bobby Davenport's 70th birthday party and he promised to return the knife, for a quid! This we have done, I have the knife (slightly battered) and he has his pound coin!
Jim McLean