Dion Boucicault. I should have guessed. Yeats would have been well acquainted with his work. The tune given for "Limerick is Beautiful" certainly fits Yeats' poem insofar as I can recall it. (By a stroke of organizational genius the computer I use and the books I read are in two different parts of the city.)

The tune given in the fife and drum site seems to be quite different. (And I notice that they write "The Rocky Road To Dublin" in ¾ time. Tsk-tsk.)