I'm going to try and summarise what we have so far, regarding William Woodham.
Born 1798, as indicated by Australian records as well as prison record.
The latter suggested he was born in Wiltshire.
(The birth in 1808 was a red herring).
Married in Easton Royal in 1828 as indicated on FamilySearch.
An adjacent record appears to have a spelling mistake,
William Bircham, and suggests a different location.
Served time in prison, 1819 & 1828-1830, separate occasions.
Probably though not necessarily transported to NSW 1829,
as indicated by comment in OPC, Wiltshire.
(realise this clashes partially with the prison story)
Possibly married there in 1829.
This all seems to happen in a very narrow period of time,
which I personally find a bit of a challenge to accept,
but it works better than any alternatives.
That leaves us to ponder the life of William's English wife, thought to be Elizabeth Whitebread on the basis that her surname is carried down into the grandchildren generation.
Such a person was born in Wiltshire in 1809 according to FindMyPast but not in Easton Royal according to the OPC. The OPC contains several births within the local tribe of Whitebreads but Elizabeth is not one of them. I think I saw it on FamilySearch that she was born in 'Grey Easton', presumably not far from Easton Royal.
However I just saw on FindMyPast an Elizabeth Woodham who lived 1810-1826, dying in Wiltshire.
I am thinking that this is the Elizabeth Whitebread said to be born in Wiltshire in 1809, in which case we may be looking for an entirely different person.
Doing a search in GRO's new database I found an Elizabeth Woodham born 1800 who dies in Risbridge Union in 1847. A quick lookup on Google revealed that Risbridge Union is (or contains) a poorhouse in Suffolk, a place I can imagine the wife of a transported convict to end up.
However this is all a matter of weaving a story through some convenient data.
I may be looking at data from two or three Elizabeths.
I'd be interested in your opinions and suggestions.
-DC