Thanks to everyone. The cassette given me was just a home made copy. Up to now I couldn't even be sure it was a professional recording apart from the obvious quality. I looked up The Jolly Beggarmen. It is the same recording. Another site lists The Jolly Beggarmen as:
Tommy Jenkinson: Vocals & Mandolin
Charlie Clarke: Vocals & Mandolin
Joe White: Vocals & Guitar
Johnny Carroll: Banjo, Vocals, Guitar & Tin Whistle

Produced and Engineered by Paul Waldron at Trend Studios, Dublin.

So we know who they are and that they were in Dublin.
I will follow up on this but it is thanks to you that I am this far.