No the argument doesn't hold for catholic schools TFM.
All the polish immigrants who have recenty entered this country send their dcs to the catholic schools and they are not middle class, they are nearly all on minimum wage.
CofE policy, however, is a disgrace. With them, their schools ARE in affluent areas.
It is the CofE schools that are giving the Catholic ones a bad name. I wish people wouldn't lump them together