Hi
Have been researching Penrhyn Isa family. I'm having trouble with my computer at the moment, keeps freezing, won't write much until I've got that sorted out.
Have a look at [130] in Ceiri's book, top right. There are errors, so don't take too much notice of the details for the moment.
John Roberts' children are by 1st wife, Mary Jones, died 1806. My interest is in the descendants of his daughter, Elizabeth Jones; your's in John Roberts jnr.. John snr remarried in 1809, moved to Hafod y Wern, his 2nd wife's home, and died 1812. His son John took over the tenancy of Penrhyn Isa in 1809. In John snr.'s will the children have 'surname' Jones, following the Welsh tradition, but John jnr. was involved in the English legal system because of a famous murder at Penrhyn Isa. He was referred to in that case as John Roberts, and he adopted surname Roberts.
John jnr is at Penrhyn Isa 1841 Census, age 60 (should be 60+); also William and Margaret Hughes, both 25+; I assume they're married. There's a William Hughes, 7; and 2 female servants.
Census 1851 you've got William Hughes, Head, 39 and wife Margaret, 36; and children, William, 17 and John, 9 (I assume John Roberts Hughes born 1841). Penrhyn Isa is in parish of Llanfihangel-y- Traethau. Early records for the family are to be found in that parish church registers, but later in Llanfrothen parish. Ll-y-T church is the other side of the Dwyryd estuary, and difficult to get to; whilst it's ony about 2 miles overland to Llanfrothen church.
Moving back to Charles Williams. You say:
Anyway, I've already taken the plunge & started adding the details to my (public) Rob Davies' Family Tree in Ancestry. So far, I got as far as the all the Census records for Margaret plus her death records. From her husband, Charles' 1911 Census record it indicates they were married in 1863 (although I can't find any evidence to back this up) & had 8 children -- only 7 are on the Census records. .........
I assume that you interpret the figure given for 'completed years of marriage' as 48. I think it's 40 with a little ink blot at the top of the '0'; compare with the '8' in the 'no. of children' column. 40 makes more sense when you look at birth date of first child, c. 1872. There's a marriage in UK BMD, Ffestiniog Q4 1870 11b 751, Charles Williams to Margaret Williams. In North Wales BMD, it only gives date by year, not quarter. It gives possible variations in 'surname' if the father's surname is different to that of his child. There is an explanation on the website. There are 2 different surnames for Charles, Williams and Charles; and 2 different for Margaret, Williams and Hughes. NW BMD also says whether it was a Church or civil marriage. If church they say which church and you can check the parish register. Unfortunately this was a civil marriage, probably in a 'chapel', nonconformist church.
Emyr