It would certainly help to be able to find them on the 1861 census - and I have tried. There are countless James Williams of course, and stacks in or from Gloucestershire, as well as other places, including Lancashire. I tried looking for Suzanna in the hopes she was born before census date in 1861. I looked for James/Jas son of James/Jas, born Gloucestershire/IOM living in IOM or Liverpool (Everton) without success. We would need more information to spot a James son of James Williams anywhere else in the country without the recognisable wife Sarah, birthplace IOM, or sister Suzanna. I suppose his marriage to Henrietta was in Liverpool? Would it be possible to track down a birth for younger brother 1869 Christopher if he was born in Liverpool? Not sure what that would prove though.