Re: Not my field of expertise
"When the cleardown is run, the unique id for the person is stored, and the date it was deleted. This cannot be tied to any personally identifying data by itself. Nothing else is retained"
This only works for very, very simple organisations. Most organisations will be worried about being sued or regulator investigations. Those organisations will have to store somewhere the identity associated with the unique id in order to defend themselves.
As soon as you do that your data subject can be reidentified from information which can reasonably be expected to be... whatever the precise wording is.