Hello Liam
I believe this is John's father, though note the spelling Whitton with a "h":
Name: WHITTON, HENRY
Initials: H
Nationality: Australian
Rank: Sergeant
Regiment/Service: Australian Infantry
Unit Text: A.I.F. 2/3 M.G. Bn.
Age: 35
Date of Death: 30/04/1942
Service No: WX/4758
Additional information: Son of Thomas James Whitton and Minnie Whitton; husband of Delce Lambeth Whitton, of Inglewood, Western Australia.
Casualty Type: Commonwealth War Dead
Grave/Memorial Reference: Column 134.
Memorial: SINGAPORE MEMORIAL
Service Record
Name WHITTON, HENRY
Service Australian Army
Service Number WX4758
Date of Birth 11 Oct 1906
Place of Birth PERTH, WA
Date of Enlistment 23 Jun 1940
Locality on Enlistment MAYLANDS, WA
Place of Enlistment PERTH, WA
Next of Kin WHITTON, DELCA
Date of Death 30 Apr 1942
Rank Sergeant
Posting on Death 2/3 MACHINE GUN BATTALION
WW2 Honours and Gallantry None for display
Prisoner of War No
Roll of Honour Unknown
As you can see he has no known grave, hence his inclusionon the Memorial.
Unfortunately the NAA is being difficult so I can't search the records, But you may find this interesting in the mean time:
The Lost Battalion: Australia's 2/3rd Machine Gun Battalion