You have made a mistake with Georges birth year!
If he was born c 1842 he would be 8 in 1850 when arriving in Australia.
The passenger list has;
WEBB
George, 24, Labourer, born Wilts
Elizabeth, 25
Sarah, 3
That would make George born c 1826.
Elizabeth 1825
Sarah 1846-1847 ( she could be nearly 4 when arriving)
There are only 7 Sarah Webbs born Wilts 1846-1847 on FreeBMD
Did she have a second name that you know of?
And only a few George Webb marriages to an Elizabeth 1845-1850 in Wilts.
But they may have married anywhere other than Wilts.
Do you have;
Georges Australian Death Cert or Elizabeths?
Did they have any other children in Australia?
A birth cert of one of them may give Elizabeths maiden name. Then you can look for a marriage in England.
Unfortunately spending money on Certs is often the only way to track people back.
Trish
