I remember Ian Campbell telling me he thought Cosmotheka were only really original act to emerge in the 1970's.
not sure he was right, but the genius of Cosmotheka was that they didn't bog off to isolated communities for material - they actually listened to our grandparents, who all seemed to know fragments of music hall songs. they researched the songs so they knew them totally. Then they found a performance style that communicated with folk club audiences - and explained to us the elan and humour of the Victorian performers.

They were quite brilliant.