Rafe Spall (“Trying, “The English”), Oscar nominee Bérénice Bejo (“The Artist”), “Sherlock” co-creator and showrunner Steven Moffat and “Skins” co-creator Bryan Elsley head shows at the 2026 Series Mania Buyers Upfront, an invitation-only event unspooling on March 23 at Series Mania, Europe’s biggest TV festival.    Spall plays opposite Jenna Coleman (“Doctor Who,” “The Jetty”) and Katherine Kelly (“Happy Valley”) in Moffat’s “Number 10,” one of the big highlights of this year’s Upfront. Bejo