Zippy would be a disaster in the role. The reason Martin had to resign was because he had lost the respect of the House. Nobody ever respected Zippy - not Geoffrey, not Rod, Jane or Freddy, not Bungle, not even George. And anyway, what would MPs address him as? Not Mister or Madam Speaker - as far as I can tell, Zippy is a hermaphrodite (as opposed to George, who is clearly homosexual).