I have pretty much stopped watching these British dramas based on real murder cases because, even though they are all separate cases, these investigations seem to often cover the same story arc. So they have little room for imaginative storytelling or structure.
I decided to watch this show, however, because I really like Timothy Spall and Anne Reid, him all the way from his Mike Leigh films and her from her Coronation Street role decades ago. They also seem to only pick good productions to appear in. They were both excellent in this miniseries, Spall perhaps award-worthy in fact. Their and other performances in the cast covered up what indeed did strike me as the usual story arc I mentioned above. The detective inspective shone while not showing anger, violent tendencies, or other outbursts that afflict many tv mystery dectectives.