Young Actor's Scrapbook.....A new "discovery" in Hollywood, but a glimpse at Peter Lawfords scrapbook reveals that the handsome English lad is no newcomer to the screen. He began an acting career under Director Monte Banks in London at the age of seven and was soon dubbed the "Jackie Coogan of England." Later he made three trips around the world with his father and mother, Sir Sidney and Lady Lawford, appeared in an American picture in 1938, traveled some more and returned to Hollywood in 1942. Starting then in juvenile roles, he was given increasingly important parts until now he is cast in his first leading romantic role, in Metro-Goldwyn-Mayers "Son of Lassie.” He won this opportunity for stardom with a powerful performance as Irene Dunnes son in "The White Cliffs of Dover."It wasn't until after the outbreak of World War II, when British currency was frozen stranding his family in this country with little resources, that Peter again returned to Hollywood. In first role he picked