You could be right, McGrath. A Belloc scholar once told me the info about Chesterton (and Chesterton and Belloc were good friends), but reading it myself I thought the same as you.
I thought perhaps the musical phrase belonged to some other odd snippets of tune found in the book.
Recently Martin Wyndham-Read wedded Belloc's words for "Sussex Drinking Song" in this book to the Irish rebel song "The West's Awake" (having first discarded Belloc's tune), and the song is catching on.
My favorite song is the one about the Pelagian Heresy. But I would like to hear the song that ends ".. and I will sing Gol-ier" if it exists. The hyphen is how Belloc punctuated it on the title page. Dave could be right, it's really "go leor".
Any other theories. or songs?
Blessings,
Barbara