Hello, I could not seem to work out how to reply to the two very kind people who sent me great links and information, so I hope you see this as take it as your reply.
As you suggested, I browsed the Killeedy PRs until end of 1848 and no other baptisms for Patrick Riedy and Ellen Foley, so I'm guessing Ellen was the last child born before the death of her parents.
I made a note of the baptisms for children of John, Robert, William and Michael Riedy also. These are the exact same names of the children of Patrick and Ellen. The eldest two children Martin Riedy and Mary Riedy came to NSW earlier than 1855 and Martin sponsored the youngest children. The boys were teenagers and Ellen was supposedly 9 in 1855 when they arrived. However, if she was born in 1842 as per the PRs, then she would have been 13 years old when she arrived in Australia. I cannot see any reason why they would have put her age down. I wonder if the fare was cheaper if she was younger? It actually leaves a better gap between her age and the boys, unless there were some infant deaths.
This RIEDY (note spelling IE) family seem to be the only one in Killeedy though there was lots of FOLEYS.
I'm so delighted to have a baptism date for my Ellen Riedy who was my father's grandmother. I trawled Ancestry.com for hours but could not find anything. Maybe I overlooked the 1842 date. A lesson learned!!!!
Once again many thanks for your help. It really makes a difference when someone has local knowledge!!!!
Regards
Chrissy