Now I have got that out of the way I can progress with something more sensible. The last line of the 1954 definition seems to have been overlooked for too long.

The term does not cover composed popular music that has been taken over ready-made by a community and remains unchanged, for it is the re-fashioning the re-creation of the music by the community that gives it its folk-character.

So, yes, by that definition 'Blackbird' by the Beatles is not a folk song. However, a chap at our club plays an acoustic version that he learned by ear and that has now become a Swinton standard in its now mutated form. By the 1954 definition, that version is now a folk song. No Man's land, as recorded by Eric Bogle, would not be a folk song but your version, Raggy, and many others would be as it has been re-created and re-fashioned many times. The same can be done to many songs and, while 'I don't like Mondays' is not as likely to be re-fashioned in the folk style it does not mean it cannot become a folk song.

Now, going back to the opening post. Those who sing from crib sheets to ensure that they sing it in just the same way as it always has been are indeed restricting the folk process. Those who use crib sheets as an aide-memoir are doing no such thing. So, maybe those who insist on re-creating folk songs exactly as they always have been done are indeed contributing to the demise of folk music and putting people off attending folk clubs.

DtG