This is him in 1916, but I'm struggling to find a birth record.
First name(s) William J R
Last name Bass
Birth year 1893
Age 23
Admission year 1916
Admission date 17 Sep 1916
Hospital 18th General Hospital
Rank Private
Service number 424556
Company / squadron A
Corps Canadians
Transfer year 1916
Transfer date 30 Sep 1916
Archive The National Archives
Series description War Office: First World War Representative Medical Records of Servicemen
Piece MH 106/1105
Register type Hospital admission and discharge registers
Description British other ranks and Colonials; operations.
Record year range 1916 Sept. 17-Sept. 25
Country Great Britain
Record set British Armed Forces, First World War Soldiers' Medical Records
Category Military, armed forces & conflict
Subcategory First World War
Collections from Great Britain, UK None
https://www.findmypast.co.uk/transcript?id=GBM%2FMH106%2FP2%2F855856