My favorite British period adaptation is North and South. See this fun MV for why :)
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NS is my third-favorite 19th-century novel (behind Jane Eyre and Our Mutual Friend, both of which also had excellent adaptations).
I am lucky in my 19th-century novel loving soul: most of them have excellent adaptations, from various Trollipe novels (Pallisers! OMGLOVE), wonderful abundance of great Dickens stuff, Austen overkill, Jane Eyre and other Bronte works, Gaskell novels, Wilkie Collins stuff, Hardy etc.
In fact, if they ever adopted Bronte's Shirley and Gaskell's Mary Barton, I'd be set forever.