It is prudent, IMO, to point out that MPs have the ability to confirm to LEs that they are fine and do not wish to return. LEs are then bound, IMO, from my understanding from asking an officer, to respect that wish.
In such a high profile case as this has been, the Police could not just simply call off the search. They would, IMO, have change the narrative to a narrative that would, perhaps, open up a wider possibility that she had left of her own volition. It is not therefore beyond realms of possibility that it is NB that has agreed to the release of today's information, given that the Police had to say something.