Regency era romance, with animal abuse, and a murder plot.

I just can’t find it. I hope it’s one book and not several I’ve cobbled together in my memory. There is the untamable girl who her sponsor (?) tries to contain. One scene she’s going to the modiste and sees a horse being beaten and verbally accosts the merchant but is rescued by a peer. I think he’s a Duke.
It turns out she is the first woman he’s been interested in since returning home... he had been injured and nursed back to health by his mistress turned friend. He has a mad invalid uncle who wants her gone and him dead. The tall skinny always drunk cousin does insane things to scare her off. Like throwing half dead animals into the yard, and trying to get a half dead horse up a hill to in front of a ball. I think he thinks since she is animal crazy he can scare her out of the city. But the servants (?) keep hiding it all from her. I think they rescue some dogs?
I think they think someone is out to get her, (possibility he’ll sire an heir?) but in the end it’s him they try to kill.
The ex mistress, who has a cottage outside London ends up helping, and eventually the skinny cousin ends up with her?

I’ve been driving myself crazy trying to think of these book. I’ve head hundreds of descriptions of books, and thought I wrote a review commenting on the animal abuse because however farcical it was it was not funny! But I can’t find that either. It was in the last 10 years at most.

Any clues at all will have me very grateful!
Thank you.