Dear Neville,
“Who cares?”
Certainly not me. If not for this thread I could have forgotten that the coronation took place. I have zero interest. But I realize that my view doesn’t create what is factual for others. And I don’t know how to label this concept, but whatever it is called, it is a big factor in what the Office of the Chief Rabbi of the UK exists for. I’m claiming that you do not have an issue with Raav Mirvis as much as the institution in general. And the solution to your issue is to be aware of the facts on the ground.
I don’t know what the halachic term for vested nationalism is. But it is a real and undeniable fact. Your insistence that this cannot play a role in the halachic approach, leads way off the beaten path. But you seem not to be aware of this.