After searching FamilySearch.org, I think I've found Thomas and Ann's marriage ...

THOMAS BYNON Compact Disc #84 Pin #139201
Sex: M

Event(s):
Birth: 1823 Place: CARNARVON WALES

Parents:

Marriage(s):
Spouse: Ann EVANS Disc #84 Pin #139202

Marriage: 1842 Place: WALES

Digger - Federation Index. Victoria 1889-1901

Surname: BYNON
Given Names: Thos
Event: D
Sex:
Spouse Surname/Father: Unknown
Spouse Gvn Names/Mother: Unknown UNKNOWN
Age: 77
Age Code:
Birth Place:
Death Place: Echuca
Year: 1899
Reg. Number: 5553

A possible baptismal registration for Thomas Bynon could be ...

4 January 1824, Thomas BEYNON, parents William and Ann, b. 9-10-1822, Wern, Collier

If this IS my Thomas, he has a sister Margaret (b. 27-4-1817, Wern, Collier) and brother William (b. 5-7-1823, Wern, Collier) baptised on the same day.

Could this be a sibling of Thomas' I wonder? She was born about the same year ...

Digger - Federation Index. Victoria 1889-1901
Surname: BYNON
Given Names: Elizth
Event: D
Sex: F
Spouse Surname/Father: Unknown
Spouse Gvn Names/Mother:
Age: 70
Age Code:
Birth Place:
Death Place: Melb E Hosp
Year: 1892
Reg. Number: 2823

Unfortunately no further information was gleaned from Thomas' death certificate.

I came across this entry on the Victorian Immigration CD which could be a sibling of Thomas'. Bill Bynon told me on the phone that two Bynon brothers arrived in Australia together. As far as I can tell Thomas was one of the first Bynons to arrive in Australia so he could have been one of the brothers and Richard could've been the other. Thomas was definitely not on the Norwood with Richard and I can't find a death for Richard anywhere in Australia up to 1899 or Victoria to 1985, so I'm not sure what's happened to this Richard Bynon. Perhaps he went back to Wales? ...

Digger - Immigration to Victoria 1852-79

Surname: BYNON
Given Names: RICHD
Ship: NORWOOD
Month: JUL
Year: 1854
Age: 37
Code: B
Fiche: 070
Page: 007

The only other BYNON entry on the CD was the one below, I have no idea who it might be, perhaps a sister? I'll have to investigate this one ...

Surname: BYNON
Given Names: MISS
Ship: SULTANA
Month: FEB
Year: 1859
Age: A
Code: B
Fiche: 159
Page: 004

According to Karen, Thomas was a Captain. This is news to me! He may well have been a ship's Captain prior to emigrating to Australia so I'm going to look into this further. Here's the notes from Karen's email ...

"PARKSIDE COTTAGE MUSEUM The Museum houses some very significant items, each telling a story of Australia. Of note is the MacArthur Cloak which is made from early Merino wool taken from the first bale of wool sent back to England by Governor MacArthur. Early Riverboat trade on the Murrumbidgee is represented by the navigation maps of Captain T Bynon. Opening Hours: Mon & Tues 2pm and to 5pm
Wednesday to Sunday 11am to 5pm Entry: Adult $2 Seniors $1 Children .50c Contact: Phone 02 69591372

I took this copy out of site on Narrandera museums. The T Bynon spoken of here is the father of Thomas Bynon who married Selina Broad."

This is DEFINITELY worth looking into, thanks Karen!! :D

A possible baptismal registration for Ann Evans could be this one ...

14 March 1824, Ann EVANS, parents Thomas and Mary, Wern writer.

Digger - Federation Index. Victoria 1889-1901

Surname: BYNON
Given Names: Ann
Event: D
Sex: F
Spouse Surname/Father: Unknown
Spouse Gvn Names/Mother:
Age: 69
Age Code:
Birth Place:
Death Place: Echuca
Year: 1892
Reg. Number: 13641

BYNON, John CB 279737 Birth
Father: Thomas
Mother: Evans Ann
Event Place: Whit
Reg Year: 1863
Reg State: Victoria
Ref Number: 23585

This could possibly be John's marriage but I'm not entirely convinced ...

BEYNON, John CM 65188 Marriage
Spouse: INGRAM, Margaret Sarah Louis
Marriage Place: Amphitheatre
Reg Year: 1886
Reg State: Victoria
Ref Number: 5554

If this IS John's marriage, then these are at least 3 children.

I can't find a death for John under the spelling BYNON, so perhaps he retained the "original" spelling of BEYNON after his birth.

Digger - Pioneer Index. Victoria 1836-1888

Surname: BYNON
Given Names: Richard
Event: D
Spouse Surname/Father: Thomas
Spouse Gvn Names/Mother: Ann
Age: 14
Sex:
Birth Place: WAL
Death Place:
Year: 1860
Reg Number: 11907
Denomination:
Parish:
Fiche:

Surname: BIRNAN
Given Names: Mary Ann
Event: B
Spouse Surname/Father: Thos
Spouse Gvn Names/Mother: Ann EVANS
Age:
Sex:
Birth Place: SDHURST
Death Place:
Year: 1855
Reg Number: 5448
Denomination:
Parish:
Fiche:

Surname: BIRNAN
Given Names: Mary Ann
Event: D
Spouse Surname/Father: Thomas
Spouse Gvn Names/Mother: Ann UNKNOWN
Age: 24D
Sex:
Birth Place: SAND
Death Place:
Year: 1855
Reg Number: 3897
Denomination:
Parish:
Fiche:

Mary Ann is the only child I had listed who didn't appear on Thomas Bynon's death certificate. I'm not sure why this is so but there was a David listed as son whom I didn't have. Perhaps David was her husband? Will have to look into this further, in the meantime I've added David as a son.