Thanks for all your replies on this folks. I'll continue my investigation into it.

Martin - it'll be a while before I'm in Dublin to check the ITMA collection I think but my best bet might be to sing it at the Rosslare Singers Weekend in February. If someone there doesn't know it then I think we could safely call it 'unknown'!

Wonderful song that I very much enjoy singing now though. And a bit of history worth remembering too.