a little bird has confirmed to me that extras are available at this place, at least from some of the workers.
Yoko (not John's Mrs) is a slim youngish taiwanese who does the deed, although she doesn't usually work there apparently. She is to be found at Surbiton on Saturdays, New Malden on Sundays and Teddington on Thursdays, so my informant tells me. Maybe a bit overpriced, expecting £80 tip for naked b2b,