I'd describe both of these as accents - and even voices - from a bygone age. Nobody apart from the Queen speaks like this any more. These are the very refined, precise voices of an earlier era, and they sound very alien to the modern British ear. There is no regional marker in either of them, because that is the whole point of upper class pronunciation - 'posh' is 'posh' wherever your stately home happens to be! These accents are separated from the average English pronunciation as much by time as they are by class. 'Received Pronunciation' is the standard 'correct' but neutral pronunciation which you would hear any time from a traditional BBC newsreader, for example. It's also classless. David Cameron, the Prime Minister, is from a privileged upper class background, but he speaks with a neutral RP accent, because he'd lose the vast proportion of his electorate if he spoke like the posh boy that he is.

I'm interested as well - both are upper-class accents, but I can't pick exactly where Johns' accent comes from. Interestingly, some of her vowels turn up in Australian and NZ English.