I think you may be after the extra verses added to The Molecatcher by Gordon Hall. He started it at 1055 one night and finished it at 1125. Yes a half hour encore!

I was once at a singaround when Gordon was present. When the MC called him he politely asked whether whether he wanted one or two. The MC said one long or two short. Gordon obliged with a very very full version of a ballad. At the end the MC made the mistake of saying sarcastically 'That was just a short one then?' 'Oh yes' said Gordon 'I know much longer than that...' and went straight into The Mole Catcher.

I went to my girlfriend and this I did say:
What would you like since today's your birthday?
She said she'd like diamonds so right there and then
I gave her the ace jack queen king nine and ten.

I went for a ride on the old underground
But I tripped on the steps and I rolled to the ground.
The vicar rushed up 'Did you miss a step, son?'
I said 'No you daft @@@@@@@ I hit every one'.