I think this was the elderly guy who used to come to the lunchtime sings in the Neptune during Folk Week. I believe he originally came from Cornwall, as I remember him showing great interest in a number of the Cornish songs we sang. I think, too, that he was still around in the '90s, but then time seems to go so fast...!
I really can't remember what he used to sing, but yes, I do remember the songs being gently humorous. If it is him, the person to contact is Pete Collins, who used to run the lunchtime sessions.