| Regimental number | 4 |
| Place of birth | Quirindi, New South Wales |
| Other Names | ALLEN, Guy Llewellyn |
| Religion | Presbyterian |
| Occupation | Clerk |
| Address | Pymble, New South Wales |
| Marital status | Single |
| Age at embarkation | 20 |
| Height | 5' 5" |
| Weight | 114 lbs |
| Next of kin | Mother, Mrs Alexandria Victoria Allen, 'Tallangetta', Church Street, Pymble, New South Wales |
| Previous military service | Served for 3 years in Military Signals Troop |
| Enlistment date | 22 February 1916 |
| Place of enlistment | West Maitland, New South Wales |
| Rank on enlistment | Corporal |
| Unit name | 34th Battalion, A Company |
| AWM Embarkation Roll number | 23/51/1 |
| Embarkation details | Unit embarked from Sydney, New South Wales, on board HMAT A20 Hororata on 2 May 1916 |
| Rank from Nominal Roll | Sergeant |
| Unit from Nominal Roll | 34th Battalion |
| Fate | Returned to Australia 20 May 1919 |
| Discharge date | 19 August 1919 |
| Other details | Medals: British War Medal, Victory Medal |
| Sources | NAA: B2455, ALLEN Guy Llewellyn |