I loved the Roy Grace novels, well written, wonderful setting, a strong and likeable pool of characters. Up until the last few novels that is when it seems Peter James started churning the books out to keep the publisher happy.
As for the TV adaptation, John Simm played Roy Grace well I thought. Do agree that the actual storyline was rather far-fetched, maybe because they had to cram it into a couple of hours. It was something else entirely that had me thinking “this isn’t right” but would have to read-read the book to prove my theory and not sure I want to that that. Will probably watch the next one.