I was trying to remember this yesterday and couldn't, and googling hasn't helped. Only other over 60s are likely to remember this. The Val Doonican show was just about the most middle of the road light entertainment show ever. My parents loved it so we watched it every week. He always had guests. One regular was a British or possibly Irish group of middle-aged men (well, they looked that age to me, back in the 1970s when I was in my teens) and they sang folk and similar songs. I think they all wore Aran jumpers, possibly not always. One of them was black or mixed race, IIRC, and the rest were white. Anybody got a name for them?
It's entirely possible I'm misremembering all of this ...