If you regard it as important, then that's fine. I'm glad you feel passionately about it. It's simply that it's more important to you than it is to me, that's all.
It's more important to me than it is to you that you are falsely claiming that I am wrong, and refusing to either admit that or prove that I am in fact wrong?
Do you make a habit of going through life saying things about other people which aren't true and then shrugging off their protests with a "I don't care if what I say about you isn't true, it's not important to me whether I'm right or wrong, I just want to accuse you of things you haven't done and I expect you to simply put up with it"?
What a shameful lack of integrity you have.
You've challenged the use of slang, or incorrectness, or improper use, or however you want to describe the thing that you're challenging.
I have challenged the notion that there is a qualification called Part P.
You have repeatedly told me that I am wrong, and that there is such a qualification, and you have repeatedly refused my requests to show the validity of what you say.
I hereby acknowledge all of your requests, and your questions, but this isn't a court of law, and I think it's permissable for me to propose that we agree to disagree.
Permissible? In the sense that you don't need permission to make false accusations and then brush aside all requests to back them up then I guess it is.
But acceptable behaviour? No.
Decent behaviour? No.
Behaviour consistent with a person of integrity? No.
If the truth is as self-evident as you believe, then any rational person reading this will agree with you, and will disagree with me.
I'm sure they will, and as I said above I'm surprised that you have so little self-respect for yourself that you don't care that you come across as someone who thinks it doesn't matter if what he says is true, and thinks it's perfectly OK to falsely accuse others of being wrong.