So if by following the correct procedures she failed in the circumstances why? I can see it happening because the interview of Kate was on a voluntary basis. As soon as she was told that Kate didn't want to proceed it stopped, even when it wasn't Kate herself that gave the verbal instruction it was over.
In my opinion she did not follow procedures or any statutory instrument that I am familiar with, she was making it up as she went along.
She arrived on the scene uninvited and without authorisation.
She forced herself onto people without authorisation.
She asked inappropriate questions and made no inquiry into the welfare of the children involved, not even making a single enquiry about any of them.
In my opinion she overstepped the bounds of good practice and acted well outwith her pay grade.
In my opinion she had no business asking Kate McCann anything at all that was not connected to the welfare of the twins and even that is questionable.
The clincher as far as I am concerned was the poison pen anonymous letter she chose to write.