Susan,
Not sure I have the expertise to respond to your interesting comments - but will take a closer look when I'm more at one with the world (not at my best while recovering from the after-effects of having to have the end of my hearing aid be fished out of my ear - oh to be young again!!)
I'm not sure there is an either/or answer to the human transmission/universality of themes question, but I'll sleep on it (Niagra Falls noises allowing)
One of the magic moments of my life was sitting in a cottage about thirty miles outside Budapest discussing (via a translator) the comparable merits of the Hungarian and British variants of The Cruel Mother and various revenant Ballads with a very elderly informant of Kodaly - they don't do package holidays like that any more!
Blandy and all:
"But I'll find time for The Folk Music Virtuoso and other Bert Radio that anyone has lying around... "
Numerous of Bert's output went up for grabs some time ago here on Mudcat.
If anybody has a problem tracing them please let me know - as somebody once said, "they're made round to go round"
Jim Carroll