Complex sentence: He claimed his last victory in the Battle of Britain, and the last in 1940, on 14 November, when Galland and Müncheberg each claimed a Spitfire in combat with the No.66.
Split into simpler sentences: He claimed his last victory in the Battle of Britain, and the last in 1940, on 14 November. Both Galland and Müncheberg claimed a Spitfire each in combat with the No.66.