I was surprised to discover the tune in question is or has been used as a hymn tune. Hearing it sung at the royal wedding prompted my question.

At the wedding of a friend's daughter four or five years ago here in the U.S., a singer-guitarist performed the "Slane" tune with his own newly written romantic lyrics.

It would have been interesting to know where he'd gotten the melody. At the time I just assumed he was a folkie....