Complex sentence: The Kittyhawks were replaced by Spitfires in July 1943, and in August the squadron moved onto Sicily and to the Italian mainland in September from where it concentrated on ground attack missions until the end of hostilities.
Split into simpler sentences: The Kittyhawks were replaced by Spitfires in July 1943. In August it moved onto Sicily and to the Italian mainland in September from where it concentrated on ground attack missions until the end of hostilities.