| Regimental number | 781 |
| Place of birth | Goulburn New South Wales |
| School | Superior Public School, North Goulburn, New South Wales |
| Religion | Methodist |
| Occupation | Labourer |
| Address | Grafton Street, Goulburn, New South Wales |
| Marital status | Single |
| Age at embarkation | 23 |
| Next of kin | Father, Thomas Duddle, Grafton Street, Goulburn, New South Wales |
| Enlistment date | |
| Rank on enlistment | Private |
| Unit name | 6th Light Horse Regiment, 3rd Reinforcement |
| AWM Embarkation Roll number | 10/11/2 |
| Embarkation details | Unit embarked from Sydney, New South Wales, on board HMAT A6 Clan Mccorquodale on |
| Rank from Nominal Roll | Private |
| Unit from Nominal Roll | 56th Battalion |
| Fate | Died of wounds |
| Miscellaneous details (Nominal Roll) | *Spelt William Colbert Duddle on NR |
| Place of death or wounding | Polygon Wood, Ypres, Belgium |
| Age at death | 25 |
| Age at death from cemetery records | 25 |
| Place of burial | Cowley (St. Lawrence), Churchyard (Aust. 43), Middlesex. |
| Panel number, Roll of Honour, Australian War Memorial | 162 |
| Miscellaneous information from cemetery records | Son of Mrs E. DUDDLE, 106 Grafton Street, Goulburn, New South Wales |