Realising I'm a bit late to this party, but I too have a brick wall that seems to be linked to the Preston family of Meath.
I have (somewhere!) newspaper articles indicating that my GG-grandfather, Edward CHRISTIE, b. Meath 1816 d. Tasmania 1880, was somehow linked to the Preston family and the Gormanston estate. At one time, Irish estate lawyers were in Australia looking for Preston descendants, but we never learnt what it was really all about. There was an indication that Edward may have been the nephew of the head of the family, but I can't find a connection between CHRISTIE and PRESTON.
The 14th Viscount Gormanston was the last Governor-General of Tasmania prior to the Federation of Australian in 1901, but again, I can't find a connection to the CHRISTIEs.
Just to confuse matters, my G-grandfather, Frederick CHRISTIE, married Mary FOX in Victoria, Australia and I alway get this confused with the stories of the foxes gathering for the imminent deaths of the heads of the Preston family.
Has anyone researching Preston family from Meath found a link to Australia?
