I have just started reading 'Adventures of a Despatch Rider' by Captain W.H.L. Watson as part of my research. My Grandfather became a despatch rider and used to tell me stories about the various motorcycles he used. Although the book is about the early months of the war on the western front, it does give you an incite into the day to day activity of these brave men and is well worth a read even if you have no specific interest in Despatch riders or like me your relative served in a different theatre.