FWIW, the liner notes to "Heartstring Sessions" say "Learned from Nollaig and Maire's mother's copy of Songs of the Gael, compiled by Padraig Breatnach and published in 1922... Breatnach didn't like Allingham's choice of tune and suggested that the poem be sung instead to this beautiful air noted by him from the singing of Kate Coakley of Rahalisk, near Macroom, Co. Cork."


Two small points, for clarity:
1. Songs of the Gael, Part 1, was published in 1915.
2. Breathnach makes no mention of another tune in his text. He simply says "The above air, which is very sweet and beautifull, was taken down from the singing of Kate Coakley, who lives at Rahalisk, five miles from Macroom"