545th Siege Battery had arrived on the Western Front in time for the Allied Hundred Days Offensive. The success of the Battle of Amiens caused the Germans to withdraw from the Lys Salient and the battery had to move forward to new positions. It came into action at Doulieu on 20 September, at once coming under heavy Counter-battery fire. The following day it was pulled out and moved south to join Fourth Army, with which it served for the rest of the war.