Eliza Sarah may have married in Marylebone in 1842, but it's not online.
March 1842 Marylebone 1 207
Jennings, James
Kirby, Eliza Sarah
+ 6 other names
They may be in Brighton in 1851 and 1861. Winding up later in Clapham. James had been a draper/milliner.
Eliza born about 1811/1812, couple of census say in Clerkenwell.
Is it possible that the John and Sarah Kerby of Berkeley Court had split up?
So far not finding a death/burial for Sarah in the Clerkenwell area.
1841, Upper Seymour Street, Pancras
Sarah Kirby 65 Ind, No, not born county
Eliza Kirby 30 Milliner, Yes
Burial, 7 Dec 1834, St. Pancras
Ellen Kerby
Abode Upper Seymour Street
Age 15 yrs
Maybe? Burial at St Pancras, 14 Dec 1845
Sarah Kerby
Middlesex St.
Age 71