| Regimental number | 6 |
| Place of birth | Brisbane Queensland |
| Religion | Presbyterian |
| Occupation | Surveyor |
| Address | Indooroopilly, Brisbane, Queensland |
| Marital status | Single |
| Age at embarkation | 25 |
| Next of kin | Mrs Agnes Sinclair, Indooroopilly, Brisbane, Queensland |
| Enlistment date | |
| Rank on enlistment | Corporal |
| Unit name | 3rd Field Company Engineers, Headquarters, Section 1, Section 2 and Section 4 |
| AWM Embarkation Roll number | 14/22/1 |
| Embarkation details | Unit embarked from Melbourne, Victoria, on board Transport A2 Geelong on |
| Rank from Nominal Roll | Major |
| Unit from Nominal Roll | 3rd Field Company Engineers |
| Recommendations (Medals and Awards) |
Mention in Despatches Awarded, and promulgated, 'London Gazette' No. 30706 (28 May 1918); 'Commonwealth Gazette' No. 165 (24 October 1918). |
| Other details from Roll of Honour Circular | Roll of Honour lists David George SINCLAIR as having been Mentioned in Despatches, and having been promoted from Sapper to Major. |
| Fate | Returned to Australia |
| Family/military connections | Brother: No.5 Sapper Donald Bruce John SINCLAIR, 3rd Field Company Engineers, who was killed in action at Gallipoli on 1 August 1915. |
| Other details |
Medals: 1914-15 Star, British War Medal, Victory Medal |