Hello SRL,
by chance I found it at Amazon dot co dot UK!
I can guess it rarely appears there either.
And I would be happy to not merely share
but to GIVE you the sheet music actually;

my purchase has served its purpose,
now that this Mudcat thread
documents the variations between
the words as preserved at Digital Traditions
and
the words sung by Donald Swann et alia.

So I am quite ready to let go of my copy
and let someone else have it.
Now, if you had a Mudcat membership,
then you and I could exchange private messages or 'PM' each other
about where I could send the music.