 Complete the following phrase:  17th Durham Light Infantry remained just behind the front line preparing tramways across flooded shell-holes, and then built huts near Mametz Wood for the battalion, while the Lewis gun detachment and the band built a new divisional headquarters at Sabot Copse. The work was finished on 3 November and the battalion rested for one day before the 50th Division made a new attack on the Butte de Warlencourt on 5 November celebrated as 