Neighbours of ours when we were growing up. We spent every afternoon together after school. I think I can count the times I went into their house. Both girls had bedrooms that looked like they came out of a magazine, and both had white duvet covers and carpets. They were not allowed in their rooms unless it was to change or sleep, so they weren't allowed to play in there. And NO visitors were allowed in. Apart from one time, I only ever saw their rooms from the window outside as I had to stay in the garden. I fetched her every morning as we cycled to school together, but I wasn't allowed in the house, I had to ring my bike bell so say I was there.
They came over to out house all the time, but had to be back home by 4pm sharp. If they were late, they would get the belt.
They were never allowed more that a upright hand measure of water in the bath at night. It was a drowning issue according to the mum. The cold water had to be put on first to 3/4 of level and hot topped up to the right level, so it was always just luke warm. I did once have a bath at their house once as my mum went into labour unexpectedly, but my mum came home from hospital before bedtime, thank goodness.
For breakfast they had Pronutro, which is an instant cereal which you mix with milk (I am trying to think of UK equivalent but cant right now), and although there are loads of flavours, they were only allowed to have chocolate flavour, and it was made with boiling water not milk. It was revolting. They never had corn flakes or rice krispies, only ever this same cereal. They were only to have plastic bowls and spoons, and this was until they were teenagers so wasn't just a possibility of it breaking sort of thing.
It wasn't a money issue, their dad had a good job at an accounting firm, got a new car each year....they were just very odd.