First given name when search for son on New Zealand Electoral Roll - Island Bay Main Roll 1969, found in June 2020, possibly showing parents and brother:
Seamer, Mona, 23 Clyde St, married
Seamer, Richard Leonard, 23 Clyde St, Insurance Rep
Seamer, Barry Leonard, 23 Clyde St, Public Servant [Son]
Seamer, Robert James, 23 Clyde St, Customs Manager

Maiden name, year and country of marriage from search on New Zealand BDM website in June 2020:
1935/1054. Bride: Mona Miller. Groom: Richard Leonard Seamer

Full date of marriage of 19 January 1935 from further searching in June 2020 on BDM Search by incrementally changing the date range for the marriage.

Year and country of death, date of birth, from death search on New Zealand BDM website in June 2020:
1997/34680. Seamer, Mona. Date of birth: 29 June 1910

Full date of death of 16 March 1997 from further searching in June 2020 on BDM Search by incrementally changing the date range for the death.

Country of birth from search on New Zealand BDM website in June 2020:
1910/19493. Miller, Mona. Mother: Kate. Father: Charles

Full date of birth of 29 June 1910 confirmed from further searching in June 2020 on BDM Search by incrementally changing the date range for the birth.