Sandy Denny nor Anne Briggs are included in the lists above because their tracks have been issued on CD or EP which are available commercially in far better quality than our amateurish recordings.
Our recordings are mainly off-air from AM complete with heterodyne whistles and clicks albeit cleaned up. Or acetates that have scratches and holes (from needle drops) and with grooves full of dust. Nothing we have is remotely broadcast quality.
Sadly there are no documentary records of actual recording dates. Such documentary records, if they exist, are not in the public domain. We know that the recording sessions were in 6 weekly blocks. The recordings were made in Trefusis - the basement function room at C#H. The whole idea of a folk club was a complete fiction, an invention by Peter Kennedy. The 'audience' was specially invited but it is believed some recordings were made sans audience. Many 'takes' would have been required.
The BBC UK tx dates are on Genome - but only for episodes 1 to 6 and 8, not 7 and not 9 to 39. Some tx dates have been recorded for when the NZBC National Programme aired the transcription discs in the late 1970s.
The BFBS Archives have some off-air recordings dated 1970s.
The whole series was aired in Australia and even Papau New Guinea. Also in the USA. And in Germany incl. Europe and the Middle East on BFBS FM.
The information above comes from the BLSA Cadenza db. The information for episodes 31 and 36 is wrong. Cellar Full Of Folk is mentioned in many places as the source for Sandy's tracks on LFSC. But CFOF recordings are dated in Genome as being 1967. LFSC is dated as being 1966. So how could tracks from CFOF be used for LFSC?
There's some very inaccurate and misleading research out there regarding Sandy's recordings.
To confuse matters further the BBC Archives have files of out-takes of singers who never appeared on LFSC, but their documentary records state that they were. These are out-takes entitled "Folk Cellar" and are dated 1965. These include a session by John Pearse - who never appeared on LFSC. The out-rakes from 1965 could never have been used for LFSC (1966) nor CFOF (1967).
As an aside it would be great if the BBC and EFDSS could re-air the LFSC episodes. It is C#H's 80th anniv. this year (or something). The British Library has a full set of transcription discs in far better condition than anything we have.