Thanks Fay for your advice. I did make a few finds, but sadly didn't see your message till I got back.
I've just spent my three days in Dublin searching for a 'needle in a haystack' for Margaret, daughter of John and Ellise or Ellen Hourihane born somewhere in Cork c. 1847. Her family moved to Wigan, Lancashire by 1851 where she is the youngest daughter with siblings Patrick, Mary, Anne, Rose, Michael & John. By 1871 they were all known as HORAN.
The nearest I found was Margaret daughter of Curly HOURICAN & Ellen TOBN of Gorladoo 25th May 1846 in Durras RC records. I also found a Margaret d.o. John HOARIHAN & Norri HAURHAN 2nd January 1848 of Rossmore in the same parish record.
Does anyone know if Curly could be a nickname for John or Norrie for Ellen?
The saddest record I found was in Castlehaven & Myross where the priest has written in August 1847 'a dreadful year of famine', and in November 1847 'all are dying of starvation'. There were very few births that year. This put my own fruitless search in perspective.