The only handbasin is external and located on the walkway.
This also explains why the speed of the swirl is so much lower in a handbasin than in a bathtub.
It is sometimes called the "'" handbasin oak " "'because its size and shape suggest a bathroom sink.
So 1?bathrooms-means that there are two rooms-one with a bath / shower in it, both having toilet / handbasins.
In the US, a proper bathroom-with an actual bath in it counts as'1'- a smaller room with just a toilet and handbasin counts as a " half-bath ".
This adjusted, she later washed in the neat and impressive handbasin, with tap, plug and all, mentally apologising for reproaching the British with lack of push-pull sanitation; on removing the plug the water gurgled happily away, emerging immediately around her feet.