'If he did develop it then he did so before 1949 when it was first collected, and what connection did he have with the singer it was collected from?'
Where's the proof 'that singer' existed in the first place? I quoted the liner notes from Hark! The Village Wait which state in the first line...
''It is strange that a song as powerful and as singable as this should be so rare, yet it has only once been collected, from a man in Bishop Auckland, County Durham, in 1949.
a song this powerful should surely have more than one version, yet this one does not As Les stated it all dead ends in Bishop Auckland.