Thanks for the help and advice but I think I now have the wrong Llewelyn family ( or several wrong Llewelyns).
This is what I received from a previous look up in January;
1871 Census, Glyntai, Llandebie, Carmarthenshire
Road/Street/House: Wernewtd(?)
Mary Llewelyn, Head, Widowed, 53, Carmarthen, Llandebie
Jane Llewelyn, Daur, Unmarried, 17, Dress Maker, Carmarthen, Llandebie
David Llywelyn, Son, Unmarried, 13, Shoe Maker, Carmarthen, Llandebie
Again, this is the only David that fits with the one found in 1891, the only one from Carmarthen, Llandebie. Unfortunately David's father had died by then, so your challenge now is to attempt to find the family in the 1861 census for Carmarthen, which I do not have access to.
I know this is the correct David ( my Great grandfather) as this is a quote from one of David's daughters 75 years later "David Jones Llewelyn went to live with Auntie Mary in Ammanford, at the farm cottage at Werneyedd Carmarthenshire, when he was only 14 years old. Auntie Mary was married to a shoemaker, who also mended shoes and sold them to miner’s families. "
So the David Llewelyn aged 11 also in 1871, you quoted was not the same one.
The name of David's parents were William and Mary - he was a gentleman farmer. Is there any sign of them in 1861 or before, in that area?
Any help would be appreciated. David