Havent time to read the whole thread but my copy of The Hackney Scout Song book has the "National Anthem of the Ancient Britons" (p122 1949 edition)attributed to one W. Hope Jones who I am led to believe was a teacher / headmaster at one of Englands Public Schools - Eton or Harrow I'm not sure which now although somebody once told me which it was.

Does this answer the OP's qustion?

Dave