Richie,
Yes it's George's single stanza.

I'm not sure I fully follow your request for info on Henry Martin, but off the top of my head I think all of the oral versions of this are versions of HM. Curiously though some of the names in American versions seem to be closer to Andrew Barton. First names are easily interchangeable in ballads and Martin isn't a million miles from Barton in phoetic terms, but it's worth looking into. FWIW I can't remember seeing any 18thc versions intermediate between the 2 ballads. I have copies of the 17thc ballad and the 19thc much shortened one but nothing in between.