Wow! Thanks - there is a lot to follow up here. Pejic first!
First, this David Jones lived at Wern in llanartheny in 41,51,61 age 60,69,79 (so born abt 1780-82)and is always a farmer (of 96 acres in 61). His wife Mary is 48,59,70 in the census. (so b.1790-93.
What's certain (from Henry's marriage certs) is father David is a farmer, living in 1827, decd in1873
Hence the possible connection.
I can't find David in 1871 (age would be about 90) so it's possible he died in the 1860's but I found that WERN the farm was then occupied by a William Michael so David had definitely moved on or died.
Yes, This David had children in 41 & 51. Emiah 12 & 20, David 10 & 20, John 8 and Mary 5 & 15.
No children left in 61
It's a good suggestion to look for births - might get me to their mother.
Intriguingly, in 1871 there is a David Jones in llanartheny, of right age to be the son living at WERNFach in the village (is it just a coincidence that there is a house name connection?). However disappointingly he was born in Llanfijnydd not llanartheny so perhaps all just coincidence.
I'm not sure how to get to neighbouring parishes to look for henry's baptism but will think on that.
Despair - thanks for your comments it is going to take me some time to respond to them and I live in NZ and have to go out for the day now so it will probably be tomorrow
Thanks again
Ian