Hi Jack
Here's 1851 census - great, the whole family, you are lucky!!:
HO107/1948 fol.116 p.22
46 Princess St, Bristol
John Leaman head m 64 Mariner Devon Ashburton
Grace " wife m 55 " Branton
Susan E " dau u 23 Milliner Bristol
Eliza " " u 20 " "
Edward H " son u 15 Block Maker "
Mary A Byrnes dau m 31 Master Mariners Wife "
Sarah I Moore dau m 25 " " " "
William T Byrnes son.in.law m 34? Mariners Mate Calcutta East Indies
Henry J " grandson 5 Scholar Bristol St.Stephens
William " " " 3 " " "
James Moore son.in.law m 33? Master Mariner Ireland Curlingfare?
John Watts lodger unm 23 Sail Maker Bristol
and 1841 - no relationships given in this one and adult ages usually rounded down to nearest 5 yrs.
1841 HO107/375/4 fol.33 p.14
Prince St, Bristol, Gloucestershire
LEAMAN
John 50 Seaman
Grace 40
Mary Ann 20
Sarah 15
Susan 13
Eliza 11
William 8
Edward 5
Oddly enough it says they were all born in the county
This is as far back as I can go with the census
Mary Ann Leaman married William Timothy Byrnes
Sept Quarter 1842 Bristol 11/192
It will no doubt take you a while to digest, so come back to us with any further questions, and enjoy the research

Barbara