is this the family in question?
1871 Godir, Berwick RG10/5464 folio 100 pg 33
William Phillip head mar 68 labourer in tin plate works
Elisabeth wife b. Pembrey
Mary dau unm 40 domestic servant
John grandson 9
David grandson 6
all born Llanelly except Elisabeth
1881 Goder, Berwick RG11/5371 folio 53 pg 40
Elizabeth Phillips head widow 81 housekeeper b. Pembrey
William son unm 53 engine driver
Mary dau unm 51
John son 19 engine driver
David son 16 coal miner
all born Llanelly except Elizabeth
1891 Godir Cottage RG12/4492 folio 35 pg 5
Elisebeth Phillips head widow 91 retired lady
William son unm 63 engine driver
Mary dau unm 61domestic servant
David nephew 26 coal miner
all born Berwick, Llanelly
1901 2 Stradey Houses, Berwick RG13/5086 folio 147 pg 22
David Phillips head mar 36 coal miner
Mary wife 36
Willie son 8
Thomas son 7
David son 4
Bessie dau 2
William uncle unm 73 living on own means
Mary aunt 71 living on own means
all born Llanelly
David appears to have died before the 1911 census
https://www.familysearch.org/ark:/61903/1:1:X7NT-7GLThis death registration is a match for age
David Phillips 42 march qtr 1907 Llanelly vol 11a pg 730
and he was killed in the Cwmfelin Mine
https://newspapers.library.wales/view/3433309/3433319/231/https://newspapers.library.wales/view/4174419/4174422/78/https://newspapers.library.wales/view/3443972/3443976/95/Possible baptisms at St Elli for
William Phillip 9 march 1828 son of William, labourer, & Elizabeth
Mary Phillip 26 Aug 1831 dau of William, labourer, & Elizabeth
Marriage in Pembrey parish church 18 January 1825 for William Phillip & Elizabeth David, both by mark, witnesses John Phillip & Richard Williams both signed, Richard Williams witnessed several marriages on the page so possibly the parish clerk.
No baptism showing for John or David. Not finding parish marriages for either. Where did John marry?