Phil: Yes, I agree that an unaccompanied singer would be wise to try and reproduce someone's performance that was originally dependent on a guitar accompaniment. But then I'd always prefer to back to an original source (Walter Pardon recording, book, VWML online archive etc) anyway.

"But are we agreed that 'as written' the thing needs work?"

In the case of the St George ballad, and also the Peterloo material I'm working on right now, I'd say a definite 'yes'.

"And has my idea that in *some* cases singers may not have made the tweaks successfully sunk without trace?"

I fear it has, since I can't find it. But, yes, I'm sure it's possible to find recordings of singers who are having some difficulty bedding the words into a tune. Though this may be partly a matter of memory: as I've said before, some 'source singers' visited by collectors may not have actively sung a song for many years. And many of them were not 'performers' in the sense we understand it now, so achieving a polished rendition may not have been a priority.