First two given name from New Zealand Electoral Roll - Marlborough Main Roll 1972, found in June 2020:
RENTOUL, Annie Margaret, Wye Hills, Wairau Valley, married
RENTOUL, James Bernard, Wye Hills, Wairau Valley, farm mngr [Son]
RENTOUL, Isabel Mary, Wye Hills, Wairau Valley, spinster [Daughter]
RENTOUL, Robert Lang, Wye Hills, Wairau Valley, joiner [Son]

Preferred name, date of death, estimated year of birth, place of burial, found in June 2020 from Wairau Valley Churchyard inscriptions:
ROBERT JAMES (Jock) RENTOUL, d.13 May 1972, a. 72 [Therefore born circa 1900]
ANNIE MARGARET (Anne) RENTOUL, d.4 Sept 1983, a. 79 [Therefore born circa 1904]

Maiden name, year and country of marriage from search on New Zealand BDM website in June 2020:
1935/12132. Bride: Annie Margaret Lang. Groom: Robert James Rentoul

Full date of marriage of 31 December 1935 from further searching in June 2020 on BDM Search by incrementally changing the date range for the marriage.

Year and country of birth, name of parents, from search on New Zealand BDM website in June 2020:
1904/17795. Lang, Annie Margaret. Mother: Isabella Smith. Father: Gavin Black

Full date of birth of 29 July 1904 from further searching in June 2020 on BDM Search by incrementally changing the date range for the birth.