Firstly I forgot to say but guess you realised that all children in 1851 Census were born Tewkesbury.
1861 Census:
James is living in Chance Street [around the corner from Barton Street] and is age 50 - Grocer and Tea Dealer - living with him are:-
Elizabeth his wife is 40
Daughters:
Ann age 18 -Drapers Asst
Margaret age 14 - Scholar
Mary age 10 - Scholar
Wilhemina age 16 - Dressmaker
Sons:-
Francis J. age 15 - Grocers Apprentice
John age 12 - Scholar
William age 13 - Scholar
Georgiana Ker age 19 is in High Street as a Shop Assistant to James G. Coleman - Draper
1871 - The family had moved to Battersea
121? Grant Road
James is now recorded age 60 as a Trvelling Draper
He is with his wife Elizabeth age 50 and Frank J. Ker; Single age 25; Grocers Shopman
Georgina is an Assistant in the household of widow Jemima Spooner a China Dealer at Brixton Hill Lambeth
Wilhemina is with the Foss household and I cannot fing the others although there is a Margaret on FreeBMD who died age 19 - Ref: Cheltenham Sep qtr 1866 6a 227
other info:-
From 1850 Directory - James Kerr [sic] - Travelling Tea Dealer - Barton Street
1853 - Petty Sessions:
James Bird, Edward Davis And Richard Tompkins, Three Lads, Were Charged Under The By-laws Of The Borough With Wilfully And Wantonly Disturbing James Kerr, An Inhabitant, By Ringing His Door Bell Without Reasonable Cause. They Were Allowed A Week To Pay The Costs.
In 1855 - the son of Mr Ker, Tea Dealer was elected into the Grammar School Tewkesbury