I forgot to add the following.

I was at the Fo'c's'le Folk Club way back in 1972 'ish for a gig by The Copper Family, well just Bob & John together.
At the interval I asked Bob if they would sing a particular song in the 2nd half.
The conversation went thus:

Bob: "John, this young gentleman asked if we would sing.......(A Song)"

John: "Sorry Dad, we can't sing that tonight, because we don't have that book."

Tim Radford