I got it so wrong as I said his name was George Frederick Smart, whereas it should have been Nicholls. His sister, my grandmother, was a Nicholls and married a Smart, so that is where the confusion arose.
When I said visited, his son Ian visited my parents on a trip to the UK when I was very small and I am 60 next year! As far as I know George was a merchant seaman and he may have stayed in Australia following a voyage. I don't think he married in England as I can't find any records.