Beatrice Hyde-Clare mysteries by Lynn Messina. It's like a cross between Jane Austen, Georgette Heyer and a little bit of mystery.
Blurb for book 1: England 1816. Twenty-six-year-old Beatrice Hyde-Clare is far too shy to investigate the suspicious death of a fellow guest in the Lake District. A spinster who lives on the sufferance of her relatives, she would certainly not presume to search the rooms of her host's son and his friend looking for evidence. Reared in the twin virtues of deference and docility, she would absolutely never think to question the imperious Duke of Kesgrave about anything, let alone how he chose to represent the incident to the local constable.
And yet when she stumbles upon the bludgeoned corpse of poor Mr. Otley in the deserted library of the Skeffingtons' country house, that's exactly what she does.
I love this series soooo much and have been re-reading them over and over - and the audio books are well-narrated and so hilarious. Bea is delightful. I didn't like Kesgrave at first, but oh wow, he really grew on me and by the later books, I'm totally in love. The author's tone and writing is excellent and I laughed out loud quite a few times.