The British use the terms toilet and loo, but the only place you will see reference to a water closet is W.C. on the very old public toilets. Toilet paper is called a bog roll and yes, they get amused when I slip up and call something, without a bath in it, a bathroom. The thing is I live in a very international village. I can think of around 30 countries people are from off the top of my head. And the one thing that everyone seems to complain about is the plumbing.
Toilets: indoor plumbing was introduced hundreds of years after buildings were built here that are still standing so the standard toilet's waste pipe coils around and exits above ground (as opposed to American toilets which require a hole in the ground for the toilet pipe.) While this means a toilet can be put in room just by bolting it down, there is just not as much suction. Which leads to:
The Toilet Brush: The British students complain that the Chinese students don't know the proper use of the toilet brush in a similar way you would complain about someone not knowing how to use toilet paper. There is a toilet brush next to every toilet public and private and with British toilet design it is a normal thing to require its use.
Sinks: British sinks have hot and cold spigots instead of mixing them to a normal temperature. So, especially during the winter months, the cold is completely ignored and hot is used in short bursts for as long as scaldingly possible. I have not been able to get a straight answer as to why this is.