I would be interested to learn the name of one of these 'creative masters' if you had one - if not, why not?

We've been here before, Jim - and as I said last time, the process you describe exactly accounts for what I mean by creative masters - i.e. the uniquely gifted working-class people entirely immersed and fully coversant with the idioms & conventions of traditional song as they were with their every day labours - be it cooper, farrier, brewer, carpenter, mason, wheelwright, bricklayer, ploughman, fisherman etc. etc. I could name a couple whose names have come down to us - George Bruce Thompson, who wrote M'Ginty's Mean an' Ale circa 1911, and Tommy Armstrong (1848-1920) who wrote innumerable songs & ballads in the traditional idiom, using traditional melodies. One thing's for sure, the songs didn't grow on trees but sprang from such individual genius - however so roughly at times - and were shaped according to the genius of others and so it goes on. Names tend not to be attached to oral folklore, any more than I could tell who came up with any of the jokes currently doing the rounds. At least that particular Oral Tradition is alive and well anyway...