I’m purely guessing but if the internal staffing is not changed when a new administration, than the office culture, makeup, structure, purpose, and outcome should stay roughly the same.
Only if the office is forced to reform under each administration would it really change. If it was working fine for the Tories, they’d leave it. If anyone else thought it needed to be overhauled they might have done it.
This is what people mean when they talk about the Deep State, though they whisper it conspiratorially.
It’s government professionals, doing their jobs day in and out, no matter who rules the henhouse.
That’s not the typical application of the poophole loophole, but I approve of it.