Thanks everyone for your interest.
There are two registrations that might fit :
Dec quarter 1845 V 27 P 337
Mar quarter 1846 V 27 P 371
Both record Mother's name as Griffith.
I have found one of these, and another similar. But they both name fathers with surname Griffith, suggesting that Jane was married and Griffith was her married name.
I suppose that her father could have been listed if no other father was named??
Navan is in Southern Ireland
Yes, but John Jones says he was from North Wales, so I have to work out what he meant by "Navan". So far it seems people here think that he meant Nefyn.
This baptism fits a lot of the criteria mentioned.
Yes, that was my idea for a while, especially as Hugh was a farmer as stated by John. But I found out that Jane was Jane Williams, not Griffith. It is possible to follow this family through the censuses, etc, because of the distinctive house name of Pontycawr (if I've got that right). It was a pity but I had to rule them out.
Where did he live in Australia? Welsh newspapers can be quite good at reporting on the diaspora
That's an interesting thought. He lived at Anderson's Creek, Diamond Creek, and mainly in Warrandyte, all near Melbourne in Victoria. Do you have a suggestion and/or a source of Welsh newspapers?
I see we have not had an answer to the original query about whether Na(r)von could be a contraction of Carnarvon. I am not near enough to personally know the area but it doesn't 'feel' right.
I've not heard of Navan as being short for Caernarvon. I think we called it Ca'narvun or Car-nar-von or Cair -nar-von. However, I'm originally from Denbighshire.
I'm starting to feel that the Nefyn explanation is more likely than the Carnarvon abbreviation explanation. Thanks.