Steve, the notion of song possession as status is found in a variety of places, most notably, Ginette Dunn's research, "Fellowship of Song'. Thus singers like Bob Scarce and Bob Hart were seen, within their communities, as high status because of their repertoires and by implication, their knowledge. Now it strikes me that it wouldn't be too difficult for a singer to generate repertoire by deliberate invention. This gives entirely new 'variants' which have been processed entirely by a single singer and not by a so-called 'folk process'. Say, for example, I want a version of 'Adeiu, adeiu' and I only have the one that I have heard sung by another singer. I might, simply create my own version, add a tune from another song and bingo! No folk process involved, just art.
I collected a version of the 'Sheepstealer' from Arthur Laycock in the 1970s. It is recognisable as the same song type as that commonly sung (I am a brisk lad and my fortune is bad) but it is localised and lacks the sense of desperation found in the other version. Arthur said he got it from his grandfather. I reckon its a deliberate invention based on something else. It hasn't, as far as I know been collected elsewhere.
My question is simply, What proportion of so called 'folk' songs are of this type, artful inventions by a single individual?
Paul