Oh my goodness, this has made me laugh; all the different names for what in Yorkshire was occasionally called 'the midden'.
Also called 'the stone house' in some areas.
As it was outside, 'I'm just going to nip outside,' was a common phrase.
One expression I absolutely loathe (and can hardly bear to write) is 'going for a slash'. Used by uncouth youth whose mouths I immediately want to wash out.
I would be ashamed of my working-class self if I were caught using Mitford's 'U' words. Pretentious nonsense.
Like most posters, I say 'toilet' or 'loo'.
But perhaps the biggest laugh here was, yet again, the posturing to be "right" and of course totally off the point of the thread, as if we were all still in school and needed correcting.

Be careful all we'll all be given detention!