On the morning of the 4th orders were received, without any previous intimation that they might be coming, for the Battalion to move forward at once. The whole Battalion, less personnel of the transport and vehicles, marched out of Vaux-sur-Somme within one hour of the receipt of these orders--a credit to the high state of organisation to which the Battalion had been trained since leaving the Hébuterne area. Boutall writes: "The march was a long and tedious one and I think I am right in asserting that not a single man fell out on the way. I distinctly remember Lieut.-Col. Wheatley congratulating himself on the fact." This march terminated at a large concentration camp known as the Citadel about two miles north of Bray. At the Citadel the Battalion was able to form a vague idea for the first time of the enormous effort being put forth by the British in this already long drawn-out struggle. The concentration camp covered an enormous area on the rolling hillsides above the Somme and presented an astounding spectacle of numbers of units from every arm of the Service--gunners, infantry, engineers--besides vast stores of materials of all kinds. The roar of the guns in the inferno of the battle line seemed to speak to the troops of the great and yet increasing power of the British Armies, and filled every heart with hope and confidence. To many of those who remembered the lean days of 1915 when the British battle line was starved for men and shells, this first contact with the reality of the Empire's strength was almost overpowering. On the 5th September the Division took the place in Corps Reserve of the 20th Division, which had been withdrawn from the fighting line, and in the evening of the same day the relief of the 5th Division in the line began. The front taken over from the 5th Division was the extreme right of the line from its junction with the French, overlooking the Combles valley to the left of Leuze Wood. The 169th Brigade (relieving the 15th) took over the right sector and the 168th Brigade (relieving the 95th) assumed responsibility in the left sector. September had set in with steady rain which had already converted all the roads, tracks and camping grounds into seas of liquid mud. The Battalion, which since arrival at the Citadel had been held at short notice to move, advanced during the afternoon of the 5th, in full battle kit in the direction of the line. The state of the ground made marching an impossibility, and after sliding along for some time uncomfortably in the mud, orders were received for the Battalion to return to the Citadel. The change of plan was, as usual, received with philosophical resignation, and the men turned in to take advantage of the short respite only to be roused again a few hours later the same evening when the advance to the line began at 11.15 p.m.