The Guardian article was the first I heard of it as well. My understanding is that it wasn’t communicated at all.
Agree that it’s shit. Have been driving without incident for over 20 years, checked the DVLA website following my 2015 diagnosis and like you, said that notification was only needed if it affected my driving.
I’m “out” about my condition but if I can’t drive, I lose all my independence, can’t get to work or the shops (public transport is a challenge). And I am a safe driver, and that hasn’t changed because of words on a page...
Hopefully someone will talk sense to the DVLA and it can go back to the way it was.