On the compact disc album, "An Caitín Bán," the seventh track is "Cnocáinín Aerach Cill Mhuire"
(actually, I don't know why, they spell it 'Chill Mhuire').
This traditional song is printed and published in both Gaelic and a singable English translation; the title is variously given as "Cill Mhuire" (in Ceolta Gael 2 edited by Mánus Ó Baoill),
"The Flourishing States of Kilmurry," and
"The Airy Wee Hill of Kilmurry."

A separate Mudcat thread has been started for this specific song.

Cnocainin Aerach Cill Mhuire

I don't hear any harp on this performance: just multiple guitars, including bass, and a chorus of the brothers singing.