Having had countless hundreds of pupils through my hands over the years, it took only one explanation of my requirements as to please and thank you on the first day of term. Afterwards, an 'old-fashioned look' sufficed to prompt the good manners. Children know perfectly well what's required, but you need to insist on it, and as you say, Don, refuse to accept anything less. I also had little rules about "Eh?", "Whassat?" and "Dunno" etc. They got the idea pretty quickly. In fact, if a new pupil arrived mid-term and committed one of these faux-pas, there would be an audible gasp from the class. Why can't parents do the same? It isn't difficult surely?