Name, year and country of first marriage from search on New Zealand BDM website in February 2019:
1915/4703. Bride: Elsie Ann Catherine MacDonald. Groom: Alexander Barclay

Full date of marriage of 15 September 1915 from further searching in February 2019 on BDM Search by incrementally changing the date range for the marriage.

Year and country of death, estimated year of birth, from death search on New Zealand BDM website in February 2019:
1926/2128. Barclay, Alexander, died age 41Y [Therefore born circa 1885]

Full date of death of 19 June 1926 from further searching in February 2019 on BDM Search by incrementally changing the date range for the death.

Brian of nzolivers believes that this Alexander death record is the right one. In the 1928 Bay of Plenty Supplementary Electoral Roll his wife is listed as a widow:
Barclay, Elsie, Waipaoa, widow

Taruheru Cemetery Gisborne Burial and Cremation Records found in February 2019:
BARCLAY Alexander - 22 Jun 1926, 41 yrs, 51 Stout St, Gisborne, Ang. Plot 1055

Results from search of Gisborne District Council online cemetery search in February 2019:
Surname: Barclay
Forenames: Alexander
Age group: Adult
Age: 41
Denomination: Anglican / Church Of England
Type: Burial
Date of Birth: Unknown
Date of Death: Unknown
Date of Burial: 22/06/1926
Cemetery: Taruheru
Block: SEC3
Plot #: 1055
Warrant Number: 1383
Inscription: The:- BARCLAY's :- JAMES, AMELIA, ALEXANDER, JOYCE.

Brian of nzolivers believes that James and Amelia were Alexander’s parents.