See the Chronicle and North Coast Advertiser Friday 29 August 1919 page 5 for an account of Mitchell's accidental poisoning, death and burial.
Served in RN 1904-12, discharging as an AB. No service record has been found in UK Archives. Enlisted 25 March 1919 in Brisbane in the RAN Bridging Train as he had earlier naval service and could ride horses. Was enlisted initially as a Leading Seaman. Promoted to Petty Officer in September 1915. on 31 October 1915 in hospital at Suvla Bay, he developed severe abdominal pain after four weeks with dysentery. He was operated on for acute peritonitis and was evacuated to a hospital in Malta. He developed a ventral hernia post operation. On 5 April 1916 in Egypt, a medical board recommended his discharge from the service. This was confirmed by another medical board which sat in Brisbane in July 1916. He was RTA per "Argyllshire", arriving April 1916. Discharged late 1916.
Sources
Service Record - Australian National Archives
Chronicle and North Coast Advertiser Fri 29 Aug 1919 Page 5