 Complete the following phrase:  The London Electrical Engineers was a Volunteer unit of the British Armys Royal Engineers founded in 1897. It pioneered the use of searchlights SLs for port defence before World War I and for anti-aircraft AA defence during the war. In the interwar period it formed the two senior searchlight regiments of the Territorial Army, which defended Southern England during The Blitz. Detachments later served in the Battle of Crete and 