I found this longshot for 1851, but there is other evidence that shows it may not be too far off...
1851
HO107/1520/161/22
7 Cressden(?) St. West, St. Lukes, Middlesex
Richard Darter(?), Head, 32, Warehouseman, b. Wiltshire Wimbre(?)
Ann, Wife, 34, b. Hereford Eardsland
Susanna, Daur, 4, b. Surrey Lambeth
Ann H., Daur, 2, b. St. LukesFanny M. ?idd, Mother-in-law, Widow, 64, Hereford, Eardsland
John ?, Visitor, 22, Drapers Assistant, b. Devon
Richard Boyer, Visitor, 22, Draper's Assistant, b. Cornwall
William Lerome, Lodger, 24, Warehouseman, b. Middlesex Fulham
Margaret Chin(?), 24, Servant, b. Ireland
This is what I got when I searched for an Ann born circa 1850 with parents Richard and Ann. I know the parent's birthplaces are completely wrong, but...
St. Lukes is in the
Finsbury District, and look what we find in IGI, all baptised at Saint Thomas Chartrhouse,
Finsbury, all children of
Richard and Ann Rossiter:
Ann 8 Jul 1849 (born 11 Jun)
making her 2 in 1851Richard 12 Oct 1851 (born 21 Sep)
Peter 4 Dec 1853 (born 15 Nov)
Agnes 18 Oct 1863 (born 1 Oct)
Jessie 18 Oct 1863 (born 6 Mar 1861)
Emily Caroline 3 Jun 1866 (born 9 May)
OK, so maybe the surname Darter and the wierd birthplaces are still eidence against it, but it is a possibility?
I was trying to find a marriage using the mother-in-law's surname, but I can't quite make it out. Also, Richard and Ann are common names and the marriage could have been anywhere - St Lukes, Shoreditch, Bethnal Green, or even different counties if these birthplaces are correct. Plus the variations in the spelling of Rossiter makes it too many variables...
MJP