I can see on Familysearch 1871 and 1881 for a Margaret Jones, 1848/9, Rhymney, Monmouthshire. She is unmarried in her parents household for both, although they are missed off FS's entry for 71 and on the 1881 they are Thomas and Susanah.
Thank you ayashi - I can eliminate that Jones family as Margaret's father Thomas is on following censuses and I know this to be the correct family
1861 RG9; Piece: 4067; Folio: 57; Page: 19 - Margaret age 13 father Thomas 33 Newtown Montgomery
1871
https://familysearch.org/ark:/61903/1:1:V51Y-ZQ21881
https://familysearch.org/ark:/61903/1:1:QKXY-D6Q4I'm actually following the line of Thomas' son John from 1861c (of which I now have all census details for) BUT
I was hoping to go backwards with his father Thomas Jones born c1828 Newtown Montgomery by following his dau. Margaret from 1861c and hoping this would lead me to perhaps a second wife or a widowed Thomas and/or his parents - a bit of a long shot
I have now just found a possible baptism entry on FS that might be him giving pob Newtown and father named John mother Dorothey
https://familysearch.org/ark:/61903/1:1:X1YH-1R8although there are not any females named Dorothy in the family and father John is a Grocer (1841c)
1841c HO107; Piece: 1440; Folio: 11; Page: 13 - Newtown Montgomery
John Jones 45, Dorothy 40, John 20,
THOMAS 15 Ap., Elizabeth 11
Trying to find the correct birth entry for Thomas' son John to confirm mmn not going to be easy - you can imagine how many birth entries there are for a John Jones born in Merthyr Tydfil registration district
Thank you for your input and help - appreciated