Perhaps one of the most silent of class signals is whether a person (male or female) wears brown shoes in London and big cities on a Monday to Thursday. Fridays and weekends are permissible for brown in town, however.
This stems back to the era when men would travel to their country pile from working in the city on Fridays. Brown shoes are for country wear; black for cities. If you were wearing brown shoes in London on a Saturday it was presumably as you had travelled in from the country.
This rule is less followed these days but the top tier still known.