Campbell's piece is no relation.

Since the original scenario becomes largely meaningless outside Scotland, it wouldn't be too surprising if an Irish variant were to become reduced to a simple "we beat up a rozzer" story, though the feat is rather less impressive if the man is outnumbered. I've been assuming that Robbie's song is a form of the Scottish song (because that is what he said it was) and I still think it likely; but we won't be able to tell for sure without some useful information (what recording? what museum?) which as yet we don't have.