Thanks for all this everyone. Firstly the ages of the children on David Glens Cert are 3 males 26,22,17 and 5 females 24,20,12,10,7 the non Roses death cert 3 males 28,23,19 and 5 females 27,21,13,9,3. I think David's are more likely to be correct.Mind you this was David's second marriage and he bought children with him from Londonderry. His first wife Ane Robertson died in 1854 in Londonderry and he married Rose in 1855.
Yes where did Johanna and Francis Bernard MCHugh get together? Was it on the boat as they both were on the Belgravia or did they know one another in Londonderry. They married in 1868 Jan 28 in Napier and moved to Melbourne where they have a family. Like you we now think he was bought up by his grandparents. He is the spitting image of Bernard Francis McHugh as I have seen a picture of him on Ancestory on a tree in Australia but of course my Francis is not mentioned in that tree. Maybe those St Paul Records may show up something when they become available or his military records as you say. He was actually born in Warrington.