. . . but it's actually the opposite - council flat, out-of-work parent, terrible schools, etc. The only reason they look well-off now is because Mycroft scrimped and saved from his summer and after-school jobs to provide the necesary trappings (expensive-looking clothes and such) so he'd be in a position to rise quickly in society and therefore his chosen career. The only reason Mycroft and Sherlock are able to pull it off is because they're brilliant and taught themselves the right accents, multiple languages, violin, etc. - everything they'd need to fit in. Their parents don't really understand their need to get "above their station" but generally don't mind now that Mycroft really *is* pulling in a good deal of money and is supporting the family. Sherlock takes on a flatmate, thougb, because he really does need help with the rent!

Usually neither of them talk about it, but Sherlock is the butt of one good-natured jab too many (from John or Lestrade, probably) and can't stand it anymore.