Just finished watching Season 3 of Hidden and unfortunately this show is the epitome of the law of diminishing returns, with each season only about half as good as the previous.
Season 3 felt like it was written as 3 episodes but the BBC required it to last for 6, so the producers had to find some way of padding it out. If there was an award for "staring thoughtfully into the middle-distance" this show would win the title easily. Far too slow, entire scenes and characters which added nothing to the story, the mood or the viewing pleasure; and a complete absence of any realistic or logical policing.
Well done on season 1, but i think this programme has run its course.