These details no longer matter. Politics is about the perception of a person who seeks power.
The perception is now Johnson is a liar and sets rules that he does not obey himself.
You cannot argue someone out of a simple perception like that. The detail does not help you - as we see here, the best it does a generate a small amount of debate but it doesn't change the perception.
A more intelligent politician would say, yes, I got it wrong, I see and I was irresponsible. The issue with that is these are the reasons why he was a poor PM.
What he is really afraid of is irrelevance- being laughed at and confined to a diminished life make end of the pier speeches. That looks like his future. Even if it lucrative, he has lost that credibility he would need to tell himself and others that he was good.
Actually he was crap and so really he will make up some rubbish about his colleagues and this country being shit to him. Wait for it, because it's coming.