This series was produced by Peter Kennedy then of the EFDSS. The 39 episodes were recorded in two blocks of 6 weeks each in 1966 / 67 at a fictitious folk club in the basement of Cecil Sharp House with a specially invited folkie audience. It featured up and coming folk singers such as Martin Carthy, The Watersons, Young Tradition, and other luminaries such as Cyril Tawney, Steve Benbow, and comperes Robin Hall and Jimmy McGregor.
The BBC Transcription Service edited the takes and then sold the discs to Australia, New Zealand and the BFBS. We have off-air taped recordings in varying degrees of fidelity. And just recently acquired a pristine set of 13 episodes on discs.
There are a few clippettes uploaded to YouTube (not from me).
But we want to fill the gaps. Episode 28 is proving really elusive.