Complex sentence: After the Gallipoli Campaign, both sides had large numbers of troops available for redeployment and the British decided to move their Suez Canal defences from positions on the canal (where they had been during the First Suez Offensive) eastwards into the Sinai.
Split into simpler sentences: After the Gallipoli Campaign, both sides had large numbers of troops available for redeployment. The British decided to move their Suez Canal defences from positions on the canal (where they had been during the First Suez Offensive) eastwards into the Sinai.