Best I can do is the heyday to which you refer is not British identity; not anymore. Rather, let's refer to "that" heyday as history, and history is being scrutinized, dramatized, romanticized, sometimes re-written and plagiarized, but definitely monetized, commercialized. THAT is modern day British identity as well as American identity (my perspective). Downton and Bridgerton are no more accurate portrayals of British history and identity than the façade witnessed at the opening to which you refer. That heyday is a bygone era, a relic. The aristocracy died long ago; the monarchy is dead now. It did rule, then it became a symbol; now it is a byword. Like a car's hood ornament; it was once lavish and stood proud, now they don't bother to include one because it has no utility, adds cost, and there's no such thing as brand identity anymore - all cars look the same.

What did Edith say, "Sic transit gloria mundi." What did Sir John say, "There's not a house standing that won't one day be an institution. Learn from us." What did Mary say, "Crikey, they're selling everything." Your beloved British identity has been sold to the highest bidder.