In 1851 there was one son not in household - Jenkin.
1851 - HO107 Piece 2468 Folio 462 Page 24
17 Daven Row, Llanelly, (parents lived at no 9 same place)
Jenkin Jenkins 25, hd, m, charcoal finer, Aberdulais, Glam
Harriet Jenkins 23 , wife, Llansamlet, Glam
David Jenkins 2 son, Aberavon (nr Margam) Glam
Ann Jenkins 1 " "
**Aberdulais is in the Parish of Cadoxton Juxta Neath
Looks like Jenkin married in the Glamorgan area poss Neath and then moved his family near his parents.
*******************************
1861 - RG9 Piece 4110 Folio 106 Page 16
4 Dafen Row, Llanelly. (think this maybe same address spelt differently?)
Jenkin Jenkins 33, hd, wid, refiner tin works, Cadoxton, Glam
David Jenkins 12 son, Stonemason apprentice., Aberavon
Ann Jenkins 10 dau, Aberafon
William Jenkins 8 son, Llanelly Carms
John Jenkins 6 " "
Thomas Jenkins 4 " "
Benjamin Jenkins 2 " "
**William is the likely Granson in 1871 with Catherine
***********************************
1871 - RG10 Piece 5464; Folio 137 Page 23
Address: Daven/Davon Row, town of Berwick, Llanelly
Jenkin Jenkin 46 hd, tin refiner, Aberdilly, Glam
Catherine Jenkin 41 wife, Merthyr Glam
John Jenkins 18 roller man, Davon, carms
Thomas Jenkins, 14 son, helper refiner, Davon, Carms
Benjamin Jenkins, 12, son " "
Phillip Jenkins 1 son " "
No William. Think it likely that Jenkins' son is the grandson William. Don't think the other grandchildren are Jenkins' He had a son Benjamin at the same time, also he has a son John who is older.
Cas