I was told by the latter of the above-named suspects that the Duet Concertina player Tommy Williams nicked the oompah tune to compose/cobble together Springtime In Battersea. I also happen to have a private recording of the former suspect playing this tune at a concert in a Belgian church when the congregation/audience unexpectedly joined in, football crowd stylee. Such jolly fun . . . but I'll leave it for them to expand on the details.