Iam64
It was a brilliant finale to what has been a brilliant series.
Sally Wainwright knows people doesn’t she. She gives older Lancashire women and the Lancashire countryside the starring roles they deserve.
Good triumphed over evil, in the end . I liked the superintendent’s underplayed recognition of Catherine’s local knowledge
Also -his response to Catherine asking who’s going to look after those two little girls. Their granny he said, in fact, there are two grannies. Full circle, grannies to the rescue
That's pretty much what the reviewer in the Guardian said, too:
'Catherine breaking off from tearing a strip of Ryan to make sure his tea doesn't spoil' 
It was so good. I loved that even as she was handing in her uniform she was solving the mystery of the drugs. How are the Hebden Bridge place going to manage without her?
I'm pleased that she made up with Claire, and most of all that Ryan came out of it all so well - both his 'grannies' there for him, and no sign that Nature had triumphed over Nurture.