Jim's group, usually with Ollie on mandolin and as you say Kevin, Doug Mchattie, would either be guests in their own right at the Hampstead Folk Club, or they'd fill in at short notice if the booked
guest couldn't make it. They also had a double bass player. Can't remember his name but he was an archivist. We'd go brass rubbing together in his battered old van. He used to play with whichever group paid the most on the day!