I seem to remember having heard something in this line, the joke of which was that "Rock all" sounds rude, and it was used as a sort of punctuation at the end of lines. That, taken with the first line R. Driscoll remembers makes me wonder if this isn't another Flanders and Swan piece. The rock is much further out in the Atlantic than between Ireland and Britain would suggest, and is also disputed by Iceland and possibly whoever owns the Faroes). It is tiny, regularly washed over by storm waves, and incapable of supporting habitation. Greenpeace did occupy it a while back. The arguments do seem ridiculous, hence the attitude of the song, but the rock is all that can be seen of what is actually a piece of submerged continental crust, home to quantities of fish, and, the crux of the matter, oil.

Best wishes, Penny