That spotty guy in the baseball cap is clearly in his thirties!
RP isn't a dialect, Kalman, mostly because it's an artificial construct of a standard ("high") language pronunciation. I think the artificiality part also holds true for standard UK English, if I am not mistaken, in that the UK does not actually have any region where standard English is also the dialect.
Other than that, yes, Kalman is right in describing the relationship between dialects and language. Also in that dialect isn't just a variation in vocabulary (and pronunciation) but also in grammar.
There doesn't seem to be a band called "Received Pronunciation", but "Modern English" isn't a bad name for a band, is it?