Series Number Id: GSGS 2773a. Sheet number: [36 SW3]. O.S.O. 1915. Detail (including water & ditches), grid, arbitrary target numbers in circles, and British front (pecked), black. German trenches in red. Two revision insets by First Army Printing Section pasted in place in Rue d'Ouvert and Lorgies areas., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC15; envelope_number: 407, Manuscript on face: Yellow Road, Willow Road [inverted], Brewery Corner [normal orientation]. Manuscript on reverse: D[Coy?], O.C. 'C' Coy, OC Coy 7th Londons [City of London Battalion, London Regt.].