Halford Biffen, Canadian hospital, Taplow 1917

My grandfather, Halford John Biffen (born in Tottenham, London), was injured in the First World War and ended up at the Canadian Hospital at Taplow in 1917. He is the one circled in this photograph. His life was saved by a metal cigarette case in his breast pocket. The bullet bounced off it into his arm. I would love to know who some of the other soldiers are in the photograph because we have an autograph book from the time which at least some of the men in this photograph may have signed. It would be nice for other genealogists to see photographs of their ancestors at this time.