Complex sentence: He participated in the Gallipoli Campaign and later fought on the Western Front where he was posthumously awarded the Victoria Cross, the highest award of the British Commonwealth for gallantry "in the face of the enemy".
Split into simpler sentences: He participated in the Gallipoli Campaign and later on the Western Front. He was a posthumous recipient of the Victoria Cross, the highest award of the British Commonwealth for gallantry "in the face of the enemy".