The 1851 census gives Ann and her brother William living with their (Harvey) grandparents in Greenend, next door to their family home, in Fen Ditton, along with their various uncles and aunts. Her sister, Sarah, who is 13 is working as a 'nurse' in Cambridge.
At present no record of William found in 1861 census - possibly deceased by this time?
Census 1841 E&W. HO107 PN 67 B 10 F - P 14.
Census 1851 E&W. HO107 PN 1759 F 472 P 19.