The only connection with West Ham United Football club is that it is an East London club and Knee's Up Mother Brown is generally considered to be a Cockney song (a Cockney is a particular inhabitant of London). It's a bit of a stereotype really, I haven't heard anyone outside of TV land singing it for years and even at our family parties it was only ever done in a half-hearted joking way as part of a larger medley of old songs.

The song that Pet and Noel did starts off differently to the versions I know and the chorus is different too. In my memory no one ever did more than one verse but the chorus could be repeated indefinitely. That's the sort of dance they did though. I wonder if it's a debased form of step dancing rather like the parodies people now do of Irish dancing.