Hi Gillian
this may be your family on 31 Mar 1901, just before Joseph married Margaret A/J 1901, Neath
LEWIS, Joseph Head Married M 65 1836 Coal Miner Neath Glamorganshire
LEWIS, Eve Wife Married F 60 1841 Neath Glamorganshire
LEWIS, Mary J Daughter Single F 20 1881 Neath Glamorganshire
LEWIS, Joseph Son Single M 19 1882 Coal Miner Neath Glamorganshire
LEWIS, Thomas J Son M 14 1887 Neath Glamorganshire
HOPKINS, William J Grand Son M 2 1899 Neath Glamorganshire
RG number: RG13
Piece: 5055
Folio: 162
Page: 42
Sub District: Neath
Enumeration District: 32
Ecclesiastical Parish: Neath with Llantwit
Civil Parish: Lantwit Lower
Address: 7, Evan's Road, Lantwit Lower, Llantwit Lower
County: Glamorganshire
I could not find Mervyns birth. In the first 10 years of their marriage they had 4 children, 1 died - I expect as you did not name him, it may have been William. This means Mervyn was born between 1909 and 1915, did he have a 2nd name?
dave