Oh boy Oh! this is a tough one.
I can only see Andrew Denham Harris, his death and the Electoral lists.
I can't find his birth or any ship records.
There is an Andrew Harris, but he is a traveller and is always out and about on ships around Australia.
Catherine Flanagan, is the same.
BUT
I did see some ship records.
I will send them Private Message.
You said they married in GARNPANG STATION, is Balranald the same place?
This what I saw on the marriage record.
The birth record for 1846, saw that, the others + or - 4 years went to the USA and the UK. I would that was her well 90%.
Not that many Harris people in Tipperary in the Tithe or Griffiths Valuation, so maybe a bit more digging.
I hope this is a help
Maggsie