David Austral Twining was born in Melbourne, Victoria and was single and a Student when he enlisted with the 16th Battalion, 8th Reinforcement on 21 June 1915 at the aged of 19. His unit embarked from Fremantle, Western Australia, on board HMAT A68 Anchises on 2 September 1915. He was appointed as 2/ Lieutenant on 12 August 1916, to Lieutenant on 12 November 1916 and to Captain on 10 July 1917. He returned to Australia on 12 April 1919.

According to the Commonwealth Gazette No 62, he was awarded the Military Medal for æAfter his Officer was wounded on the afternoon of 5th August, 1916, he took charge of the scouts, and took up a position about 50 yards beyond the POZIERES MILL. He patrolled the front between BAPAUME Road and R.35.c.4.8 and reconnoitred the mill. He remained in this position the whole time from the night of 5th/6th August, 1916, until about 10 a.m. on 7th August, 1916. During the German counter attack on the morning of 7th August, 1916, he was able to bring flanking fire on the attacking infantry, and thus was of great assistance in repelling the attack. At about 10 a.m. on 7th August, 1916 he was left with three wounded and one unwounded man, and was ordered in. He afterwards returned to the position to bring in his wounded comrades, and was himself wounded while do so. The work of this N.C.O. was particularly meritorious.'

According to Commonwealth Gazette No. 61 he was awarded the Military Cross for 'conspicuous gallantry and resource in an attack. When part of the assaulting line was held up by machine gun fire, he led forward a party under intense fire, and worked round the flanks of the position. He captured the machinegun and some prisoners, and thereby prevented many casualties. He displayed untiring energy and courage throughout.'

Other medals included two oak leaves (one large and one small) and the Croix de Guppre.
Tree No. 3782