OK, a bit TIC as it's really not my problem! But just wondering if my neighbour has shot himself in the foot ---
He's a builder, bought the house next door to mine and has knocked it around and put it back on the market (though has taken 2 years to do so). It started off as a 2 + 1/2 bedroom house with a full bathroom on the first floor, where all bedrooms also were.
It's now a 4 bedroom house - 2 on the first floor, 2 in the new attic conversion. He's put a toilet in on the ground floor, and an ensuite for the master bedroom on the 1st floor (really it's just a wet room, it's not very big, but has a shower, toilet and basin). And the "family bathroom", on the first floor, has just a bath (with a fancy shower top attachment but no overhead shower) and a basin - but no toilet!
So if you were staying and sleeping anywhere other than the master bedroom, you'd have to schlep down to the ground floor if you needed the loo in the night. Would this put you off? It would me!
YABU -- just plait your legs or use a gazunder
YANBU - of course you want a toilet that's easily accessible to most of the bedrooms!