From Muriel Leo’s (nee Oliver, 1917-1998) Family Tree. Date of death given as 13 Jan 1954.
Rachel Frances Oliver (b.1940) claims year of death is 1953. Place of death provided by Rachel.

Dax Eric Clayton Lloyd, (great-grandson of Jessie Bertha Oliver b.1876) writes:
“Here is his Aramoho burial record;
Full Name: OLIVER, Gordon Howard
Date of Birth
Age: 42
Residence: 143 Anzac Parade
Occupation: Ins Inspector
Warrant or Register No.: 805
Action Date: 15/01/1954
Officiating Minister: Rev Templeton
Funeral Co-ordinator: Dempsey and Sons
Cemetery
Area
Block: H
Division: 10
Plot: 616
Remarks: Purchase Plot 5656

With an ‘Action Date’ above of 15/01/1954, Dax thinks it unlikely to wait a year from death before burial if we went by Rachel’s claim of his death being in 1953. However, Rachel might be right because Gordon was aged 42 at death, which would place his death in 1953.
Therefore, Brian will change the date of death to 13 Jan 1953 to keep in line with being aged 42 at death.

The following website has reads:
http://winsomegriffin.com/Cone/Bartrum_GeorgeNathaniel.html
GORDON HOWARD OLIVER; b. 28 Dec 1910 - his father Louis Oliver (1872-1938) his mother Maud Carrel (1883-1956); Residence: 143 Anzac Parade, Occ: Ins Inspector; he d. 13 Jan 1954, Wanganui Age: 42

Later, in October 2018, Brian of nzolivers did a search on BDM website:
1954/18762. Oliver, Gordon Howard, died age 42Y

Full date of death of 13 January 1954 from further searching in October 2018 on BDM Search by incrementally changing the date range for the death.

Therefore, Brian will change the date of death back to 13 Jan 1954. [Age of 42 at death works out correctly].

New Zealand Electoral Roll - Rangitikei Supplementary Roll No. 1 1935, found in July 2018:
Oliver, Gordon Howard, Okoia, clerk

New Zealand Electoral Roll - Invercargill General Roll 1938, found in July 2018:
Oliver, Gordon Howard, 226 Dee Street, insurance clerk

New Zealand World War II Ballot List April 1942 Invercargill
544369 Oliver, Gordon Howard, insurance clerk, 178 Venus Street

New Zealand Electoral Roll - Wanganui General Roll 1946, found in July 2018:
Oliver, Gordon Howard, 68 Duncan Street, insurance clerk
Oliver, Charlotte Amy, 68 Duncan Street, married

New Zealand Electoral Roll - Wanganui General Roll 1949, found in July 2018:
Oliver, Gordon Howard, 68 Duncan Street, insurance clerk
Oliver, Charlotte Amy, 68 Duncan Street, married

Result from birth search on New Zealand BDM website in October 2018:
1911/3171. Oliver, Gordon Howard. Mother: Maud. Father: Louis

Full date of birth of 28 December 1910 confirmed from further searching in October 2018 on BDM Search by incrementally changing the date range for the birth.

Year and country of marriage from search on New Zealand BDM website in February 2022:
1939/16406. Bride: Charlotte Amy Bartrum. Groom: Gordon Howard Oliver

Full date of marriage of 12 October 1939 from further searching in February 2022 on BDM Search by incrementally changing the date range for the marriage.