OK... Genome online DB (Radio Times listings) has 2 items for CFOF that include Sandy Denny:
Saturday 18 March 1967 17.31A CELLAR FULL OF FOLK with THE IAN CAMPBELL FOLK GROUP SANDY DENNY CLIFF AUNGIER sings and introduces on record Tom PAXTON Produced by Ian Grant
Saturday 22 April 1967 17.31A CELLAR FULL OF FOLK with SAM'S FRIENDS SANDY DENNY Bill Clifton sings and introduces on record THE BROTHERS FOUR Produced by Ian Grant
(full list abtainable via https://genome.ch.bbc.co.uk/search/0/20?adv=0&q=cellar+full+of+folk&media=all&yf=1923&yt=2009&mf=1&mt=12&tf=00%3A00&tt=00%3A00#search)
It seems these are not LFSC despite earlier reports to the contrary in some sources...
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