I grew up in a house that wasn’t plumbed for hot water on the upper floors.
The bedrooms got a sink in the hall with a single cold tap and a closet with a “water closet.” Actually, no heat upstairs either, just grills in the floor for heat to rise. This was in the US, BTW.
The separate taps in British houses are more a matter of style, since they’re easily converted to a single faucet. The plumbing for hot water is generally there.
What is more common in Continental Europe are instant water heaters. One in the kitchen, one for the bath. It’s lovely to always have hot water available, not run out half way through a shower as the tank gets cold!
