I saw the GREENBRIAR BOYS twice. Once in the very early sixties at a coffee house in Hamilton, Ontario called the Happy Medium. It was Ralph, John and Bob with a guest, the fiddle player from the York County Boys.(Sorry, I don't remember his name.)
The second time I saw them was at the Mariposa Folk Festival the year it was held in Maple Leaf Stadium. That year Rev. Davis, John Hurt, Joanie Anderson (now Mitchell), Gord Lightfoot, Buffy St. Marie, David Rae and a bunch of other people were there too. I'm pretty sure Al Cromwell, and Ken & Chris Whiteley were in the audience. At that festival the GB boys were John and Bob with Frank Wakefield on mandolin and comic relief plus Jim Buchanan on fiddle. They had a bass player too, maybe Eric Weisberg?
I also saw John Herald and the Honkies on Ian & Sylvia Tyson's show in the 70's.