It's very clear the rules don't apply if you are connected to government and your face fits -
Matt Hancock was back at work 6 days after his positive test
Boris' girlfriend moved address twice after he was diagnosed - once to leave DS and go to their flat, then to Chequers after he was released from hospital (via DS). She's now back at DS.
Robert Jenrick lives in London. His family went to their country home. He followed via his parents. Not only did people buy that, suddenly, it was ok for him to go to his 2nd home because he "feels like that his is main home" they also bought that he had to deliver that one prescription to his parents, even though they'd had regular local help with shopping and prescriptions before (and since).
Now Cummings.
Neil Ferguson pissed off the wrong people and was made to fall on his sword.
I fully expect that at some point it'll come out that Matt Hancock went to his second home while he was ill. When the questions about other homes were being asked due to Jenrick he looked very uncomfortable, yet none of the journalists asked him directly. His face still fits.