Hello Gibbo,
That is a real puzzle.
This is the brother in my tree:
Assisted immigrants arriving at Port Phillip, 1839-51
Surname Firstname Age Events Vessel Year Reel RecordItem Page Remarks
NANCARROW Thomas Blonde 1848 2144 4/4816 95
Arrived 15 Oct 1848
Thomas 22 Miner Redruth Cornwall Wesleyan Read
I have no idea who Thomas aged 20 is and how he fits in. On the image of the Bounty vessel there is no entry for a Thomas aged 20. So looks like an error.
That Eliza is from Scotland - Ely (should be Elie) Fifeshire
I did actually expect Eliza to be with her older brother. I can't see it as an error in the shipping record. They are not listed as family but Eliza separate on 'Single females not part of family' list.