Three books by two favourites: Mary Stewart's Touch Not the Cat and Thornyhold and Georgette Heyer's Envious Casca.
Touch Not has the hallmarks of one of Stewart’s classic romantic suspense novels: a beautiful woman (Bryony Ashley), both supremely confident and utterly alone in the world; a breath-taking location (the collapsing, but beautiful, ruin of Ashley Court); a discreet problem (the Court, and its expensive upkeep - whatever is one to do with this most ridiculous of #firstworldproblems). There are even several handsome men, depicting a variety of swoony characteristics, for Bryony to inevitably choose from. And, naturally some skullduggery: perhaps Ashley’s father’s accidental death wasn’t quite so accidental after all.
In the normal Stewart formula, this would unfold in the traditional way, with a few twists, an inevitable romantic pairing, and the barest modicum of actual threat. Stewart’s novels often unfold with an aristocratic coziness that precludes actual danger: the characters are so warmly ensconced in an upper crust so thick that murder itself couldn't penetrate it. (It is, I daresay, utterly wonderful to read, and her characters' self-confidence makes them better escapism than a thousand-thousand hobbits.)