Complex sentence: The Orillon Batteries are part of what is known as the "Northern Defences" which include these batteries together with Bomb Proof Battery, Hanover Gallery, Kings and Queens Galleries, Star Chamber Cave, Commons Hall and St. Patrick's Chamber.
Split into simpler sentences: The Orillon Batteries are part of what is known as the "Northern defences". These fortifications include this and Bomb Proof Battery, Hanover Gallery, Kings and Queens Galleries, Star Chamber Cave, Commons Hall and St. Patrick's Chamber.