Well, Tim, I can actually add something...

I've been puzzled for some time about the origin of the mysterious and sensual modal tune usually sung in the revival, which came - inevitably - from Bert Lloyd. He passed his version on to Frankie Armstrong and Anne Briggs, and their renditions inspired many other singers. The odd thing to me was that every version I could find in English tradition had a robust and jolly major tune (I'm guessing yours does, Tim, though I can't put my hand on your excellent CD just now). Eventually I found it in the Folk Song Journal vol. 4, p 94 (1910), where Anne Gilchrist had included a modal tune from Christie's 'Traditional Ballad Airs' for comparison with a major version from Devon collected by Priscilla Wyatt-Edgell. Gilchrist believed that the modal version was 'of considerable antiquity'. So, Lloyd did on this occasion use a traditional tune - rather than make up a modal one as he did on many other occasions - but it had a very different feel to the usual English tune. The songs on the eponymous LP are full of such editorial interventions, designed by Lloyd to present erotic song as something sexy yet delicate, and obliterating all traces of the vulgar, bawdy songs of which he disapproved.

It's all in my chapter for 'The Routledge Companion to English Folk Performance'.