He's a strange choice for the latter golden goodbye role...I have a suspicion that he's not been 100% content for some time, constantly fire-fighting, subject of much negative briefing and then, Bang! hit by COVID-19. He knows that he can step comfortably into some non-executive directorships, enjoy his fellowship (non-stipendary) at an Oxford college, and possibly even becoming the head of one of the colleges before too long. So, upon returning, from his convalescence to find he's fire-fighting, subject of much negative briefing and.... he's decided '**** it' and gone.
But he's exacted a peerage and the global economic security job as his golden goodbye.
I don't blame him for going, he has been out-of-step with the new regime from the get go.