Sure, if you have a stately home I could imagine the reason for it. No one wants to walk for 10 minutes to go to the loo in the middle of the night. But a normal 3 - 5 bedroom house does seem a bit ridiculous space wise. Especially as (at least in the south east of England) land is the most expensive part of a building. I could think of much, much, much better uses of the space for my house rather than wasting tens of thousands of pounds worth of space (in land and building fees) on bathrooms.