I suspect I have called some people from BA and banks some terrible things when I suspected they were scammers and unable to satisfy my queries.
Or maybe just some scammers got called those terrible things.

I don't understand the need to verify my identity when calling me, on my mobile number out of the blue.
Who designed this (very UK specific) ask for personal details without providing any proof that it is the company they say they are.

Yes I know GDPR and data protection laws but to verify who you are talking to when calling a private number singular to them does not appear anywhere in any law I know of.