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Zahawi? - from the sounds of it, and based on the fine it does come across as an artificial arrangement.
If he'd done the same thing properly from the outset it probably would have been fine. So many artificial avoidance schemes come apart due to the execution. Also worth saying that being fined by HMRC doesn't mean anything other than HMRC are of the opinion that you owe them money. They are not a court.
Sunak? - it seems likely that his affairs have been arranged to avoid or minimise his tax, but who knows if he's actively tried to take the piss.
Tax avoidance = legal
Tax evasion = illegal
From the sound of it, it sound 100% like tax evasion.