Yes, it was the Liverpool Ceili Band who started the jumping up and down bit, and I wouldn't be at all surprised if it was a bit of Eamon Coyne's devilment in the first place - must ask Sean Mac or Mick Coyne next time I see them. You can hear the LCB singing along to the Kilfenora jig if you click on the link (above).

But I think the "Diddly ah, di diddly ah, di ah diddly ah di da twice through for the A part" bit probably goes back to Sean O'Riada's score for the soundtrack of the film version of The Playboy of the Western World, performed by Ceoltóiri Chualann - I've still got the LP somewhere...