I do wonder how much of that still applies anyway, the extremely cosy/informal relationship between the five members can't really work in a world where one member is threatening to annexe the territory of one and support the annexation of another.

Trump wading into the Falklands debate was catastrophically stupid (not that I would expect otherwise) and chopped the legs out from the people who'd support him/their style of politics here.

So was threatening Canada, that's how he ended up dealing with Carney which from his PoV was the much worse outcome.