I am British, so what I would consider upper class is... upper class. "Middle class" in the UK means the same as it does anywhere else - educated, property-owning, suburban, high discretionary spend budget... middle class.

Sure, there's plenty of people who will try to redefine it to mean people with substantial investment/property income who send their kids to private schools and own second homes abroad... in general to justify claiming that cuts to capital gains and inheritance tax are 'to help the middle class'. But that stockbroker-belt lifestyle is more specific to what you'd call the 'upper middle class'. And even stockbrokers aren't sending their kids to Eton...