I suggest that you (respectfully) update your informant.
He would laugh in your face. He's quite a jovial fellow.
I have already explained why your are wrong. Nothing I can do if your understanding is so limited.
No breach of the wording you found is needed for the purposes I gave. If it bothers you so much, work out some ways how that can work for the result you imagine it "must".
Instead of accepting that you don't know all about everything, you think you must know it all. It doesn't fit with the subsection of knowledge you know about. You don't ask how it works , you just say you know better. It doesn't seem to have crossed your mind that details would not be in the public domain, even though, the reasons for that are glaringly obvious. All that would be expected of a forum troll.
The people who write the words are evidently more sophisticated than you have been able work out. The link you discusses certain tasks of detective work being given to banks.. But the HMRC have their own facilities. For example the guy told me they (HMRC) tie undisclosed accounts together. I wasn't surprised at all, but I didn't realise the significance at the time. That would mean that the the discussions you're referring to are irrelevant. The banks
don't have to do it. Obvious really, it would leave the banks open to all sorts of legal comebacks, and they could never do it all, because banks don't share account details. The House of Lords obviously didn't spot that.
So the public have that layer of apparent assurance they can be presented with so they don't get upset. They become misdirected, as you are.
I daresay there are other levels of mechanisms going on. I don't need to understand them, because I know the guy and what he is. Simples.
You very definitely aren't anywhere near him in question in terms of knowledge of the laws and things done to deal with them. Or intelligence or imagination, or lack of naivety. That isn't an insult, I'm not either, it' a statement of fact.
Amusng that you think you are, if rather sad.