The Scots or the Australians?
Both, of course

If whinging were an Olympic event, the Brits would win gold, silver and bronze. And the consolation prize. And they still wouldn't be bloody happy.
because the only English people I know who are serial complainers are all chavs.
Well ... that's sort of the definition of a chav, isn't it? Everything is someone else's fault, and the whole world needs to know about it. Seriously, though, I get the impression that a lot of Brits are deeply unhappy; they're not just moaning for the sake of it. There
is something intensely irritating about England that I can't put my finger on.
It's quite possible it wasn't a tirade at all. It sounds like it a lot of the time, even when not!
I used to have conversations like this with my (Taiwanese) SO:
her: [loud recitation of every crime, real or imagined, that finley has ever committed, in chronological order]
finley: Can you calm down and stop shouting? If there's something wrong, tell me what it is normally and maybe we can do something about it.
her: [genuinely surprised] I'm not shouting. I am NOT SHOUTING.
Sadly, I have less patience these days and just tell her to STFU. Even more sadly, that actually works.