Premise sounded interesting - closed door mystery. I have not read other books in this series.
Another book where the author chooses to just have the main male character/lord of the manor have endless affairs with everyone, as did his father before him, who has the same name, so it's really hard to keep everyone straight. The main male character is so awful, but several of the women he's carrying on with are still hanging around - despite them all being in like their 60s.
I don't buy that this detective who's there just by chance solves a 30+ year old closed room murder in the span of 3 or 4 days when the solution is not even that complicated. Surely someone else would have checked it out?
Also, the couple is there on their honeymoon, at what sounded like a manor turned inn, but everyone else there is a member of the family or family "friend". Are they the ONLY paying guests? Kind of a weird idea for an Inn. Come stay in our Scottish manor with our dysfunctional family and the former and current mistresses of my father and his father before him. Great vibe.
Ending felt a bit rushed and kind of out of nowhere.