Maybe a birth registration of their children is a way forward ~
1871
RG10/5682/117/22
Llwybyr ? Iath, Froncysyllte
Robert Hughes, 44, puddler in forge
Margaret, 38
Edward, 13
Benjamin, 9
Thomas, 6
Margaret, 4
Catherine,11 months
All born Llangollen parish
Most likely birth reg for Catherine is
June q, 1870, Corwen, v 11b p 447
I thought that Benjamin might be easy but not sure about the registrations
gnu