PAVILION, SELSEY. "THE PERFECT MARRIAGE," which comes to the Pavilion, Selsey, on Monday, serves as a return ticket to motion picture prominence for David Niven, who resumes his Hollywood starring career following six years in the British Army. The glossy, high comedy, as sophisticated as champagne, is an adaptation of a New York stage success by Samson Raphaelson. Loretta Young, one of the screen's foremost beauties, shares the starring honours with David Niven. They make an admirable team, each complementing the other in good looks and individual comedy style. Thursday's feature, "LONDON TOWN" stars Sid Field and Kay Kendall.