He said “a british voice,” which it almost certainly would be with those words, just like the voice saying “howdy” in most peoples heads is American. It’s not saying all British people would say that.
Most Brits would know that as a Texan accent honestly but it's a matter of semantics. I'm sure Americans realize "spot of tea?" and "chewsday" aren't the same accent even if they sometimes use them a breaths away when depicting "the British" accent. If I was to depict "the American" accent I would say "Tomato"
There is only really the one british accent that's ever depicted in our media/whatever media makes it over here, so I'm sad to say almost certainly we do not.
That's why we only ever seem to imitate the one (or accidentally mix them, apparently). It's the only example we've got and we assume everything is that one. I don't know where any of those areas are any more than I know the sociological difference between them, and if I had to name any others, I don't know what I'd do.
Tomato still has mild southern variations ("tuh-may-duh/ter-may-der,") but it is a solid choice now that I think about it.