Thank you for clearing that up for me. In fact I have Joshua and Sarah down as parents for William. His son Thomas, my great *3 grandfather emigrated to South Australia after his marriage to Jemima Grant and the birth of their first son James. I have Stephen, Charles, Job, John and Mary Ann as Thomas' siblings, but may be wrong. I wasn't sure if Joshua was the right father for William or not. Your explanation certainly clears up why the alias disappears and reappears.
I'm currently trying to work out which Grant family Jemima, his wife, came from as her father was John and there are two of them. I think she is the daughter of John and Elizabeth, siblings Eleanor, Martha, Dinah and Sarah, of Rowde. There is another John Grant from further south, but I don't think he is the right one. Could you throw any light on this perhaps?
Many thanks to you.
Bronwyn