I've yet to encounter anyone on the folk scene who does in fact genuinely believe they are a 19th century farm labourer, or even merely the reincarnation of one.

Me neither - that's what I'm saying. Although there is Ewan MacColl's very queer notion of 'Method Singing' which is as patronisingly absurd as anything Sharp & his bourgeois cronies ever came up with. I think any Folksong Singer - great & small - invents their own fantasy world anyway, just any model railway enthusiast does. Whether they then go on to insist that fantasy has any objective currency is another matter entirely, although it could make a good horror story, rather like the Ventriloquist Dummy segment of The Dead of Night which deals with a similar sort of (potential) psychotic trauma in which things blur rather...