Joe Offer:
It appears Colcannon (The Little Skillet Pot) is not copyrighted. I found this buried in some biographical data at livesofthepipers.com. I recently found what appears to be a statement that Sean O'Nolan never filed copyright on his songs.
QUOTE:
O'Nolan wrote much verse and many songs. Most of his work has been forgotten, but a few songs are still occasionally heard. Mick Moloney recorded "Me Uncle Dan McCann," 2002. Margaret Barry recorded "If You Ever Go Over To Ireland" in 1955.

His songwriting efforts had something to do with a folk tradition, and it is unclear if he has gotten proper credit for things he has written, or conversely, that he has been too generously credited with songs which have a traditional or unknown source. In the same remembrance mentioned above, author Josephine Patricia Smith wrote "Strangely enough, Shaun, like too many of our Irish song writers, neglected to attend to the very important detail of copyright, and as a consequence received no financial compensation for his authorship."