Hi Shanko
I know you were asking for census info on this Mason family, but since this is proving quite difficult (the only Charlotte Mason I found on on the 1871 census was living with her married sister, Frances Carrington and brother in law Richard Carrington in Southwark - it stated Charlotte's occ as Hair Net Maker - Charlotte's age stated as 20 yrs).
I then found this birth entry, which might be her:
MASON, Charlotte
September 1849
St George Southwark
Volume 4
Page 73
and a marriage for Keziah Mason:
Dec qtr - Lambeth - 1d 514
Found a Keziah Mason on 1871 census, aged 21, living as a lodger in St Marylebone - occ machinist.
Not sure if any of that will be of help, but it's all I could find.
Regards, Leah.
ps (could William Mason have died before the 1861 census or do you have him alive at any point after that? If you are just going on what the marr cert says, it could be that Charlotte did not mention her father was deceased). Just a thought.