"If you're not doing anything illegal, why not cooperate" makes sense - unless of course a bunch of blokes in plain clothes grab you on the tube and shoot you in the head eight times without giving you a chance to cooperate; or a masked gang breaks down your front door and shoots you on the landing.

Or to go back a few years, it didn't make any difference for the Maguire Family that they cooperated with the police who arrested them on the basis of faulty information, and tehn proceeded to construct a fraudulent case against them in order to cover up up that mistake, with the result that the family were jailed for years.

At leat it appears that this precedent has not been followed in the case of the Forest Gate episode.

Mistakes get made, and that can be understood. But what can never be excused is any attempt to camouflage those mistakes in a way that compounds the damage to innocent people.