Complex sentence: Between 1941 and 1942, he commanded the 2nd Battalion Duke of Cornwall's Light Infantry until 1943, when he was appointed as a staff officer in the 51st Infantry Division, which was stationed in North Africa.
Split into simpler sentences: Between 1941 and 1942, he commanded the 2nd Duke of Cornwall's Light Infantry. After holding that command, until 1943, he was a staff officer in the 51st Infantry Division, which was stationed in North Africa.