Stranger at the Hall by Mary Kingswood

The newly discovered heir to the barony arrives to claim his inheritance.
Cameron Saxby is contented in his life as a bank clerk in Edinburgh, knowing that if he works hard, he has a good career in front of him. But fate has a different plan for him – as heir to the late Lord Saxby. Inheriting the title drags Cameron away from his unassuming Scottish roots and drops him into the wealthy estate of Maeswood Hall, surrounded by deferential villagers and the resentful family of the late baron, a man who left such a trail of misery in his wake that someone murdered him.

Cass Saxby’s life is already settled – she’s betrothed to the village clergyman, who talks charmingly of love and seems uninterested in her vast dowry. But the arrival of the new baron upends her quiet existence in a multitude of ways, and forces her to make life-changing decisions, while revelations from the past may put her very life in danger. Cass and Cameron must unearth the secrets of the late baron’s life and fast, or one of them may become the murderer’s next victim.

This is a complete story with a happy ever after. Book 6 of a 6 book series. A traditional Regency romance, drawing room rather than bedroom..