This is probably Douglas McLean McDonald (different spelling of surname). He was killed at Gallipoli in the First World War and this obituary for him was published in the Public Service Journal
The late Sergeant Douglas McLean McDonald was killed in action at the Dardanelles, was a son of Mr. Hugh McDonald, Castlecliff, Wanganui. He enlisted at Ashburton in the Main Expeditionary Force, being appointed a sergeant in the Mounted Regiment. He subsequently became attached to the Headquarters staff. After working for some years on a Government survey party, Sergeant McDonald joined the Christchurch branch of the Lands and Survey Department, and was assistant to Mr. Buckhurst, Crown Lands Ranger. For two years previous to enlisting, Mr. McDonald held the position of Crown Lands Ranger at Ashburton. He was a conscientious and popular officer, and will be greatly missed by his associates.
The late Sergeant McDonald served in no less than three contingents during the Boer War. At one time he was reported killed, but turned up shortly afterwards in New Zealand, to the surprise and delight of his friends. He received the King’s medal, the Queen’s medal, and two clasps for his services in the Boer War. Public Service Journal, 20 October, 1915, p. 52.
See also his entry on Auckland Museum's Cenotaph database.