Leonard and his colleagues were one of the many bands who performed as many as four sets on the same evening, with the earlier shows often poorly-attended as many of the regulars were in other parts of the country playing their own shows.

Leonard tells WalesOnline:: "We played our first song, and when it had finished the figure in the darkness applauded. We turned to him, bowed and told him he was a wonderful audience - and the largest crowd we'd played to in some time!"

When the set was over he went over to thank the listener. "It was Hendrix," he recalls. "He was dressed in a black military jacket. My heart stopped, my mouth went dry and I broke into a cold sweat.