I was looking at this thread recently and then had a chance to speak to Sandra Kerr at C# House yesterday. She told me that the words were the version from Folk-Songs of the Upper Thames (which explains the absence of some of the verses in the broadside) and that the tune was written by MacColl.

She agreed with my view that part of the appeal of the song, in this version, is the unfinished feeling at the end of the tune, leaving you hanging in the air, and likewise of the story.

Richard