My favorite British word is bullocks.
As in Sandra?

I always thought the word was
bollocks, as in the phrase "dog's bollocks" which is roughly equivalent to the old US phrases "the cat's meow" or "the bee's knees" (yeah, I know, I'm showing my age).
Also a UK beer, which IMO, has to take the prize for the best name ever on a bottle of lager:

But, I have definitely noticed certain British words and phrases in newspapers, particularly. "Flat" is used more and more for "apartment" - especially when describing a Manhattan location. I also occasionally see "lift" for "elevator." "Randy" has been turning up, too. Perhaps it's just me, but I've always associated the use of the word "loo" (here in New York City) with rather pretentious types of folks. What's next,
pissoir??
On the other hand, language is ever-changing. It's nearly impossible to keep it from "morphing" - though heaven knows, the French have tried - so it may simply be a case of evolution.
That said, I'm quite knackered so I think I'll put the kettle on and see what's on the telly.
Signor V.