Hi, Gareth - this Google search brings up a bit of information, but my Internet service is so slow today that I can't pull much of it up. The song is in the new Essential Ewan MacColl Songbook that Peggy Seeger put out last year. You'll find a very interesting comment about the song here (click). There is an intriguing mention in the Digital Tradition (click) that Barbara Dane used to sing "Ballad of Ho Chi Minh" - but alas, no lyrics.
Well, I guess that's all I found. I guess we're going to have to break down and buy that songbook. I've been meaning to do it for quite a while.
-Joe Offer-