You might want to have a look at A BALLYNURE BALLAD in the database here. No source is acknowledged, but it is described as "Scots"; a version appears in the Greig-Duncan collection (vol.VII, which I don't have). On the other hand, the text is very close indeed to that in Hughes' Irish Country Songs (I, 1906, 32-6), and so is the tune (though for some reason it seems to have been transcribed with one-too-many flats in the key signature), so perhaps that is the uncredited source.

I don't know how close it may be to the set the McPeakes had.