I don't know. I was wondering if Norman Wisdom played it himself, or if it was a sound effect. I know Norman was an excellent pianist, but sometimes they do use sound effects for pianists, whether the actor can play or not.
It was my life's ambition to play a musical instrument to which I am pleased to add that I succeeded in so doing in my late fifties. I played classical music but never made it to the Albert Hall. Apparently there is no demand for people playing the comb and paper.
Oh yes there is when Crowcroft serenaded Nora , perhaps you could serenade Pearl for Terry , Tony and John when they want Pearl to provide sustenance for their "Meeting" , might get them a nice squashy cream cake aside from the normal butties