> they could have talked to members of the Mark Anderson family (from whom MacColl apparently got the version in Singing Island which Martin Carthy learned and Paul Simon copied...).

It has been alleged (on what basis I'm not sure) that Mark Anderson did not exist, and that MacColl himself was largely responsible for the song's perfect combination of melody and lyrics. Considering the controversy surrounding the trad status of that seminal version, it's incredible that they didn't.

Or...did they?

Was MacColl even mentioned?

(The melody resembles the best-known version of "Henry Martyn.")