A couple of days ago I received an email from a Hannagan in Australia. The writer's name is Nola Marshall, and she says:
I recently found your homepage for Hannagan.
I am a descendant of the Australian Hannagans.
My Grandfather was William Francis Hannagan, brother of Martin John Hannagan. I have information and photos of this side of the family if you are interested.
This bit of the family is a little confusing - at least at this point. William and Martin were the sons of Francis Hannagan (born in 1825) and his second wife, Mary (nee Cairns). On the family tree as it currently stands, I have two William Hannagans - I suspect they may be the same person, and we've got the information a bit confused. It isn't entirely unusual for people in the Victorian period to give two children the same name, if the first died very young. However, I don't have any evidence for this, as yet.
We'll keep you informed when I hear back from Nola.