No RTim, contemporary song is no part of the Folk Tradition. 1954 definition. That's the point. What is it that is being preserved and passed on (additionally) by printed material.

For research definition is all.

I would have thought it wise to separate folk dance and folc culture (eg corn dolly making) from music and maybe music from song.

Almost certainly it will be necessary to decide if one is speaking of England, or including Wales, Scotland, parts of Ireland or all of Ireland, and/or traveller traditions.

Then the researcher can point to the 1954 definition and the research on which it was based, and start to identify the previous and/or subsequent singers who departed from the transmission model presupposed by that definition.

That might (unlike all the silly arguemtns about horses) show that the 1954 defintion was flawed.

It leaves unaddressed how one will define folk music if that defintion is flawed, and that in turn will upset the stuff from the Oxford Dictionary of music about what modes and intervals are found in folk music.