I have read all of the books, and love them. The TV series is significantly different - even from the beginning, but especially now. I knew an 'activist vicar' from that era quite well, and am sure that the events in the books are based on Robert & Rosalind Runcie's life in those times.
They are less good on detection, much better on characters and stories, but well worth searching out.
I find the TV series a bit irritating with storylines rather shoe-horned in, and why on earth are a clergyman, detective and secretary doing a post-mortem? Can't they afford an actor to play a pathologist?
But there is some excellent period atmosphere, and they do touch on issues current at the time, which are not always remembered. I rather think someone has been leafing through old women's magazines!
I don't want to spoil the books by disclosing too much, but Sidney follows a different personal path than in the TV series.