Charles is calling himself just 'Thomas' in the 1891 census in Chippenham, Wood Street, lodging with the Mahoney Family
1891 - RG12/Piece 1593 Folio 101 Page 23
born Donhead St Mary, a Wheelwright. A Married man ... no wife present.
The Family are together in Chippenham in 1901.
RG13/Piece 1920 Folio 47 Page 28 @ 88, London Road
Thomas Brown 39 Head of household born Wilts, Donhead St Mary: a Wheelwright
Ellen Brown 40 Wife born Middx(?) London (as corrected by Census Clerk) Waterloo
Alfred Brown 17 son Donhead St M: a Railway Clerk
Ernest Brown 15 son ditto
Births Dec 1883
BROWN Alfred Sidney Tisbury Reg District 5a 197
Births Jun 1885
Brown Ernest Tom Tisbury 5a 210
Here they are as suspected in Donhead in 1891 census, transcribed in with the Masters family ... even tho its clearly a different household and schedule number ..
RG12/Piece 1624 Folio 62 Page 4 @ Donhead Street
Ellen Brown 30 Wife (we know that CT was in Chippenham) - born London, Lambeth
Alfred Brown 7 son born Donhead [St Mary]
Ernest Brown 5 son ditto
Annie Crocker 27 Married Visitor born Dorset, Weymouth
Frank Crocker 1 son Donhead
Lillian Crocker 9/12 dau ditto
I think you will have to get one of the boy's Birth papers to establish Ellen's former name - I did look to see if Charles married as Thomas, but its hard to say really ...