Percy's Story.
Lt Percy Douglas was the son of the Rev. Percy Douglas vicar of Great Sutton. Many machines carried not only the pilot but also an observer to operate cameras and wireless and man some of the various types of machine guns: there were various combinations of Vickers guns and Lewis guns. One of these observers was Lieutenant Percy Douglas who started his war as a Territorial by joining the Liverpool Scottish on the day after the war started. Was in France by November 1914 at the age of 17. 
Wounded near Ypres in May 1915, he was then commissioned into the Army Service Corps in July. He was wounded again in August 1916 and transferred to the RFC in August 1917 joining 11 Squadron. On a single morning on 12 March 1918, his machine guns claimed five enemy scouts (fighters) seen to go out of control and another two aircraft two days later. Unsurprisingly this won him a posting to the School of Air Gunnery, a development in the improved training of aircrew.
The Birkenhead News. Saturday, February 6, 1915. When he had joined the Kings Liverpool.
Percy spoke briefly during one of the IWM voices of the First World War which can be found here https://www.iwm.org.uk/history/voices-of-the-first-world-war-war-in-the-air His account is the last one.