Thank you
Found William b 1804 m Mary in 1851. Mary would be about 50 in 1855 when Isaac was born?
Going with the Isaac Roberts aged 17 in 1871 living with his uncle Thomas Roberts and aunt Caroline in Bagillt if I've followed Thomas back correctly he did have an older brother William b abt 1833 Holywell son of John Roberts and Jane Davies. This is the only Isaac Roberts I can find in 1871 that might match. Looking at the original census he is definitely indexed correctly at 17. Thomas and Caroline's son was born in Liverpool and Isaac is shown as the same the rest of the family Holywell although Caroline is shown as different birthplaces on different censuses.
I suppose with the 1861 census missing it might be very difficult to find them.
Carole