Seem to remember something like 14th Edition had distance sink to socket, but a waste disposal unit would likely be plugged in within inches of the sink, although under the sink not on top, so the regs today talk about equipment being suitable for the environment. Baths and showers have minium distances, and old photos of me and sister as babies show use having a bath in the kitchen sink, it was not that much before that, when the tin bath would be unhooked from the wall, and placed in front of the living room fire to have a bath.
We can argue until the cows come home, what makes a room a bathroom, however we are in real terms looking at two things, common sense, and what the LABC inspector will say, and in the main, if it makes sense, then the LABC inspector will allow it.
I remember the argument over socket heights, 700 wheel has a radius of 330 mm so any sockets at or below that height are likely to get damaged. The hand wheel is a bit higher, so could make contact at 600 mm, but that would likely be known by the user as she/he would be scrapping their hands, so 350 mm is a sensible minium for sockets. But this is not the case where the socket is supplied to work a fridge etc. The big problem was not too low, but too high, wheelchair users can't jump up to use a switch.
The cooker isolator I remember was a problem, set at 1200mm yes within the regs, but with a counter top between switch and floor it was out of reach, as to the thermostat, most are designed to look down on them, to read them, so need to be below 1200mm for a wheelchair user to see the temperature set. And unless you have a stair lift or lift, how will a wheelchair user get upstairs? The main consideration there is for sockets not to be at a height where the bed can hit them, so either under the bed or over the bed. And LABC inspectors in the main are flexible if given a good reason why something has been done.