There's a few threads of connection between Downton Abbey and other British fiction. Yes, Marla and I enjoy Downton, despite John Green calling it "crack cocaine for old people". But on to the threads:

Downton's set in the Yorkshire Dales, and occasionally the signposts point to, or the characters refer to the nearby village of Thirsk. Thirsk is a real village, where the real Alf Wight went to practice as a vet. He wrote about those experiences in what eventually became All Creatures Great and Small under the pen name James Herriot. He fictionalized the name of the village as Darrowby. I wonder if in a few seasons of Downton Sigfried Farnan will be tending the Earl of Grantham's horses? Or that Tristan would care for the pigs?

Downton is filmed at Highclere Castle, where another period piece was filmed, this time a comedy: Jeeves and Wooster, based on the stories by P. G. Wodehouse. Yes, House fans, Hugh Laurie is hilarious. I can imagine the feckless Bertie Wooster coming to call on Lady Mary. Perhaps Violet, the Dowager Countess, is one of Bertie's great-aunts. If I had time and video editing talent, it'd be fun to intercut scenes from Jeeves and Wooster with Downton. I do imagine that Jeeves and Mr. Carson would get along famously, though.

A video series similar to Downton was Upstairs, Downstairs, set circa 1930. The premise is similar: the comings and goings of the aristocrat family contrasted with those of the servants. I'd like to recommend it, but I really don't think it holds a candle to Downton. Upon reflection, the main reason is the title character, Downton Abbey itself. Upstairs, Downstairs was filmed in what was obviously a BBC studio, and as such, can never really capture the texture and richness of the landed gentry the way the actual locations of Downton can.