The origins of Pat Cooksey's song the sick note have been well documented for years, Sing Out Magazine, Rise up Singing, The Furey's Songbook, The Dubliners Songbook, etc, etc, all listing him as the author, what therefore is the basis for other claims to the song and presumably royalties. Mike Cross Noel Murphy Robbie O'Connell And all the arranged byes.

Seems all you need to do is change the title.