I've always been intrigued by this photo of my father riding this motor-bike in the English countryside. I think the photo was taken by my mother as l have other photos with the same farming background. Probably taken in the 1920's. Is it a Douglas; l'm not sure.
"The British Douglas motorcycles were first produced at the Douglas family's Bristol workshop in 1907. Based on a previous firm's design, these first bikes were 350cc machines. The company prospered, and during WW1 produced over 70,000 machines for the war effort. In later years the bikes would prove to be popular with dirt-track racers, in part thanks to their revolutionary front disc braking system. Seeing the successes of their motorcycles in action, Douglas began to offer their own, off-the-shelf, dirt-track racing machines of either 500cc or 600cc in the late 1920s.By the mid 1930s, sales were declining and the company was taken over by the Bond Aircraft and Engineering Company. Motorcycle production continued however, through WW2 and into the 1950s, with the final bike, a Dragonfly, produced in 1957. "
From: http://www.oldclassiccar.co.uk/douglas.htm