Lynne Frederick, 39, an actress with small parts in several British films and ex-wife of Peter Sellers and David Frost. Her roles included “No Blade of Grass” (1970); “Vampire Circus” (1971); “Henry VIII and His Six Wives” (1972); “Schizo” (1976); “Voyage of the Damned” (1976); and “The Prisoner of Zenda” (1979). In the latter film, a remake of the 1937 classic, she played opposite Sellers. In 1985, Miss Frederick won $1.5 million in a London court battle with the makers of “Trail of the Pink Panther,” which she said insulted Sellers’ memory. The film was released in 1982, two years after Sellers died, and was crafted from discarded clips from the five previous Pink Panther movies. She was married to interviewer Frost for 17 months and divorced in 1982. She subsequently married Harry Unger, a Los Angeles physician. In Los Angeles on Wednesday of what a county coroner spokesman described as natural causes. Toxicological tests are pending.