HI
Had a look at the Death index for South Australi and found this

Harriet Marchant
died 9/8/1964 Charlesworth Park Adeliade South Australia reg no Ade 978/5516 aged 80 years

Henry Thomas Marchant
died 28/8/1958 Paynechan Eastwood South Australia reg no no Nor 879/5350 aged 79 years.

Cheers Marg