Joyce
Doesn't appear to be a ready connection. My ancestors that came to Australia were Benjamin
Gibson and his wife Emma. They came in 1856. Benjamin's father was a Thomas, but he died in Newcastle (drowned) in 1828. Benjamin did not have a brother Thomas.
However, Thomas came from a very large family and there could be an off chance that your Thomas was some form of cousin to my Benjamin. I have not yet traced all the families of Thomas' brothers, so I don't know all the descendants.
Gibson was of course a very common name in the area.
Peter