Whit Stillman has set his return to the big screen for the first time in 10 years. “A Night at Claridge’s” (working title) marks the Oscar-nominated filmmaker’s first feature since 2016’s “Love & Friendship,” and will reunite the director with “Nobody Wants This” star Adam Brody following their previous collaborations on “Damsels in Distress” and “The Cosmopolitan.” Meanwhile, “Downton Abbey” star Laura Carmichael has been cast as the lead. Altitude will introduce the project to buyers in Cannes. Popular on Variety Set in autumn 1943 in the build-up to D-Day as South England is flooded with American soldiers, “A Night at Claridge’s” follows Miss Roach (Carmichael), a publisher’s reader bombed out of her London flat who is relieved to find lodgings outside town and start a friendship with Vicki, a vivacious German woman. But at the boarding house her life is made hell by Mr. Thwaites, a preposterous bully. As per the synopsis, the arrival of a happy-go-lucky American officer, Lt.…