I've come up with Irish activist Tom Maguire (not McGuire) who also appears to have been an author penning 'The mind of Wolf Tone'.
Jim would certainly know more than I however at risk of allowing my imagination to run away with me, but also in light of Jim's post above, I can see how the song may have been attributed to Castling. If the song was current among the working class singers in the 1920's, to use the song in the Music Hall and associate it with the 'Stage' Irish songs of the period, would have toned down it's political sentiments.
I've probably produced a work of fiction here, but it's all that occurs to me. No doubt you will put me right.
Nick
P.S. Pop Maynard had the song as well.