Complex sentence: After the Affair of Katia the area was held by British forces with their main bases at Romani and Kantara carrying out regular patrols of the contested area until the issue was resolved at the Battle of Romani in August 1916.
Split into simpler sentences: After the Affair of Katia the area was held by British forces with their main bases at Romani and Kantara. During this time regular patrols were carrying out over the contested ground until the issue was resolved at the Battle of Romani in August 1916.