Harry Mainwood (1882-1949) does not strictly belong on this Chailey site but his brother Frank is included and as I have information and a photo of Harry, I am going to exercise more poetic licence and add him to the Chailey roll-call.
Harry and Frank were two of John Oldaker's pupils at Newick School and he recorded information about both of them (below), and also asked them to send in photos.
Harry was a pupil at the school between 1889 and 1896 and he enlisted on the 23rd June 1916. He joined the 24th Middlesex Regiment and was given the number PS/3455. The 24th Battalion was a reserve battalion but as is clear from the medal roll, Harry served overseas with the 17th, 1st, 13th and 1/8th Battalions (in that order).
John Oldaker's roll notes that Harry went to France in November 1916 and was back in England by the end of the following month. No service record survives for him (and there is no entitlement to a silver war badge noted either) but a single fragment with his name on it does appear in a service record in WO 363 noting "debility" (below).
My thanks to Simon Stevens for the photo and notebook entry. Extract from WO 363 is Crown Copyright, The National Archives.