As I recall . . the dates in the Penguin BEFS are unlikely to be early enogh to suggest where the songs were collected . . (that is the R Vaughn Williams / Bert Lloyd collaboration, isn't it?). Also as I recall, there are songs in there collected from places a long way from the place names mentioned in the songs (doesn't actually prove anything, I realise).
My suspicion is that the only certainty here is that, whatever place of origin you come up with, someone will disagree with you . .
But hell, does it really matter?
G.