RE the above, on its listing for Sandy Denny, Attic Tracks vol. 3, discogs has the following information:

        BBC Light Programme “Cellar Full of Folk”, rec. March 6, 1967, broadcast March 18, 1967
A11        Hold On To Me Babe
Written-By – Tom Paxton

BBC World Service “Folk Song Cellar”, host Alex Campbell, rec. December 2, 1966, broadcast January 11, 1967
A12        Green Grow The Laurels
Written By – Traditional
A13        The Boatman
Written-By – Traditional

So (if my supposition above is correct, and the dates given are accurate), the last 2 dates cited might be applicable to LFSC 31.

For general info: I found this image of an actual disc (LFSC 13) on an old "for sale" listing, if anyone is interested in what they look(ed) like:
https://www.popsike.com/Folk-Song-Cellar-BBC-Transcription-Disc-60s-LP/270710538933.html

also some images and track listings for LFSC 35 and 36 here:
http://www.strawbsweb.co.uk/albtrack/bcast/transc.asp

Cheers - Tony