 Complete the following phrase:  In 1917, after enduring a harsh winter, the 17th Battalion was involved in most of the major battles as the German Army shortened their lines and withdrew back towards the Hindenburg Line, seeing action at Bullecourt in May, Menin Road in September and Poelcappelle in October. At Lagnicourt, on 15 April, the 17th took part in a defensive action along with four other battalions from the 5th Brigade, defeating a counter-attack by a numerically superior German force, and recapturing the village that had been lost along with a number of guns that the German force had taken off the Australians earlier. In early 1918, the battalion was involved in repelling the German spring offensive, undertaking defensive actions in the Somme Valley, before taking part in the 