I don't think that one is true.
"By the time he'd gotten up, the postman had already been".
Yeah, that's not true. There are some weirdness with some words though, like snigger/snicker, apparently snicker is the original word, which over has morphed in to snigger, but not in the US.
I have had friends who live in the U.K. tell me how odd and old-fashioned "gotten" sounds to their ears, though. It must be one of those things that varies from region to region, or perhaps it's only in specific constructions.
The US squeamishness with coarse expressions is quite amusing. The universal use of 'bathroom' for toilet is one of them and 'going to the bathroom'; as in 'the dog went to the bathroom on the floor'.
But Deckerd, "go to the toilet" is also a euphemism - admittedly it's a bit less euphemistic than "go to the bathroom," but you aren't going in there just to say "hi" to the toilet, right?
By the way, strictly speaking, one should say "go to the bathroom" to refer to the room itself only in private homes. The public version would be "go to the restroom." Just sayin'...
But me, if the dog did something on the floor, I would personally be pretty darn blunt, as in "Your damn dog pissed/urinated all over the damn floor." There is a time for euphemism and a time to call a spade a spade.