Thank you learned associates.
The singers will not necessarily be Irish and I doubt the actors would be able to get their chords around gaelic and I certainly don't want a mangled song.
For the record... the majority of early transported convicts were English. Of all transports the Irish made up about 25% (many came mid 19th c and, of course, many were political prisoners. The Scots were less that 4% of the total. Mind you... they also sent us Africans, Canadian rebels and Maori troublemakers......

I will have to take a wild guess at the song but at least your input has helped me.....