Arabella Davies Law - Australia help please

[kiterunner]

This is on a side-branch of my tree - Arabella Davi(e)s Law born 15 Sep 1837 Southwark, Surrey, baptised 6 Oct 1837 St George the Martyr, Southwark, parents William and Charlotte. In 1841 the family are all in the workhouse, Charlotte separate from the rest of them:
1841 census

Arabella is listed as Isabella on this census. (She was named after her great-grandmother who was never sure whether her name was Arabella or Isabella.)

Here is the rest of the family in 1851 but no Arabella / Isabella and I haven't managed to find her elsewhere:
1851 census
Now I have just found that she appears on some public ancestry trees marrying a Henry Barnett in Victoria, Australia in 1863 and dying in 1876 in Adelaide. She doesn't have a middle name on either the marriage or death index, just Arabella, but apparently she and Henry gave one of their children the middle name Bristow, which would fit with my Arabella.

Can anyone find anything to prove / disprove that Arabella Barnett is my Arabella, please? (It's only a distant twig of my tree so I'm not planning to pay for certificates.)