Interesting thread. My band have just recorded the song. We sang it at a gig the other night. At the end of the gig a guy from Islay told us that on the island there is a tradition that the song was written by one of the many Ulster men who came over to work in the marble quarry there. I could believe that. Just a continuation of an exchange of peoples and culture between Ulster and the Western Isles that has taken place for centuries.