It is always possible that some of the Kellow's living in Australia are descendants of Lt Robert Kellow.
From what I have read and understand, Robert came to Australia on board the Scarborough with the First Fleet. He then had two children with Catherine Hart (a convict who also came out with the FF, on the Lady Penrhyn.)
Robert Kellow b.1790 and Johanna Kellow b.1791
It is "presumed" that Catherine and the children, returned to England with Robert in 1792. There do not appear to be any further records of them in the NSW BDM's, so it would appear likely.
Perhaps Robert and Catherine had more children, and then some of their descendants came back to where their ancestors were born ???? It would be good if it could be proven one way or the other !