In the 1891 census
Carolyn Gosen, age 17, servant,
birthplace - Portsmouth, Hampshire
William Gosen, age 16
is listed as Head of household
his sisters Agnes and Elizabeth are now going by the surname Saunders
Amelia J. Saunders, age 38, mother
birthplace is listed as Alderney, Channel Islands.
I went to Free BMD to look for the birth of Carolyn again and found her
Carolyn Amelia Bell
Portsea, Hampshire
b. Dec qtr 1873, Vol 2b, page 462
there is also a Henry Francis, same qtr, vol and page, could be a coincidence or another son.
I still can't find a marriage for Amelia Holman/Bell and William Gosen and I am thinking they probably never officially married.
Amelia started using the surname Saunders as early as 1891 and I can'f find a marriage for her to Richard Saunders either. I found a marriage for Richard in Dec qtr 1898, Pontypridd, Vol 11a page 916 but it doesn't have an Amelia that page with any surname. So are you sure they married.
It does appear that Amelia Holman/Bell/Gosen/Saunders could be one and the same person.