I’ve lived in two apartments with the setup OP described, and they were both built 2003-2006. But I’ve not had it anywhere else, so it does seem constrained to a specific window of apartment developments

▲

alimbada 10 hours ago | parent [-]

Interesting. Every place I've lived in has been older than that so that makes sense.

	▲	user5994461 6 hours ago \| parent [-]
		It's a setup seen in a lot of new builds flat from the 2000s and 2010s, which is a very large amount of the housing stock in London for flats (There has been so many constructions!).