Dd has found class in NI different from London, though I suspect London can be different from elsewhere in England.
Class in London can be quite coded. Visible wealth (new car, jewellery etc) is often not a good idea. Everyone uses public transport. The value of your property often depends on how long you have owned it, rich people often have a modest London house and a large second home, and plenty, like us, are property rich, cash poor. Out of school activity tends to be organised so MC kids can ski, play the piano, take part in sport and are dragged to the theatre.
As a blown in key parts of the class code were not relevant. (School, where you live etc) and DD was probably judged on her elderly car and her lack of interest in clothes, or sunshine holidays. She observed the higher status accorded to someone with a affluent small businessman father and another whose mum was very senior in the public sector and who lived in Balmoral. Also in the mix was that so many of her colleagues seem to have known not only each other, but each other's families from nursery through University and so though friendly it was initially hard to break in.
She still reckons that she has it easier than a friend who comes from one of the more working class sectarian areas of the city, so is neither blown in nor has those existing, deeply embedded, social networks.
DD then bought a house which seemed to cause colleagues to rethink. Was she higher status than they had thought, failing to understand that Londoners stretch themselves to start paying a mortgage as soon as possible.
I went to a convent boarding school in the UK and I remember an Irish friend, from an affluent farming family, observing that the nice thing about Ireland was that everyone knew each other. In her circles they probably did.