I think I've found my John Behan (father of my grandfather). I have a John Behan born to Daniel Behan and Elizabeth Murphy on 27 Jun 1858. His address given as Derry. Parish/District given as Banteer, Co Cork (which is actually a Townland). Roman Catholic church baptism. Sponsors Philip Behan and Elizabeth Behan.
Although, John Behan is given as 5 years older than this on my grandfather's birth certificate.