Ronald Fraser served in the Honourable Artillery Company from 1914, was seriously wounded at the Battle of Beaumont Hamel and was invalided out: his left arm and hand were permanently disabled. (Beaumont Hamel, a little village just inside the German trenches, was the objective on the first day of the Some, 1 July 1916; it was finally taken in the Battle of Beaumont Hamel, at the end of the “battle” of the Somme, on 13 November 1916.)
This information comes from Mark Valentine (pers.comm. to this website); some of it is corroborated from the authors’ site of Valancourt Books.