Hi - William was William D not William A (someone misread the entry). William Davidson Dumbell whose English birth index details I posted a short time ago.

And yes, the other son was John Thomas Dumbell, birth index details from England also posted.

One of William Davidson Dumbell's sons was killed in WW1. Horace Cunliffe Dumbell killed 23 June 1917 (Air force) "Son of Mr & Mrs William Davidson Dumbell of Tauranga, Thames". He is in a cemetery in Belgium, Messines Ridge (NZ) Memorial.
Horace Dumbell b.19 April 1896 was at Thorndon School Wellington in 1903 when the family was living at 15 Featherston Terrace.
They also had a son Harold John b.6 April 1900 at the same school - his full name was Harold John Craddock Dumbell d.1979 in Auckland, married Norma Muriel Griffiths in 1925.

I had a big search for Marrion, and finally found her recorded at her marriage to William Henry Triggs in 1882 as Mary Hannah Dumbell.

While I was searching I found something really interesting - the shipping record on the "Tararua" from Melbourne to Wellington, departing Vic 1 Oct.1870, which included amongst the saloon passengers Revd Mr Dumbell aged 36 occupation Minister, Mrs Dumbell aged 34 occupation Lady, two "Master" Dumbells (occupation "gentleman") aged 10 and 6, and "Miss" Dumbell aged 8 (occupation "Lady").

If they left England on the ship "Hydaspes" it looks as though it went to Victoria. I'll look.

Sue