I'd be very surprised if such a law existed Kathryn. There's plenty of insane things going on in politics ATM, but that would be up there in the ranks of completely and utterly nuts.
And that's the UK for you! The room sharing laws are only for people who live in state housing though, and it's more to ensure that a large family get a larger house when their youngest child with a mixed gender sibling family is 5.

When you have your own home, you can do what you want. But the state won't pay anything to help you.


I do have cousins who every year or so would chop and change who shared a room with whom. That worked best for them, as they all got a turn at their own room and they all stopped sharing before they started to really resent their sibling.