In Hayes in 1881 there is a widowed Annie Anderson, 31, from Guildford, Surrey (let's put her aside for the moment as a possiblity).
Assuming Ada Anderson is the daughter of either Emily Bradford's sister or Thomas Lane's sister:
The Lane family are in 1871 (with children Eliza and Sarah) and in 1861 in Hayes (with Eliza). No relatives hanging around in either of those censuses.
In 1841 in Stanwell with Thomas there seem to be possible sisters: Maria Lane, 11. Jane, 9 (mother possibly widowed, so less likely to be younger siblings). The Lane girls seem a little too old to be having children in 1875, though.
In 1841 in Old Windsor with Emily there is a brother George and the possiblity of younger siblings. Parents are David, 27, Sarah, 25.
I can't access 1851. By 1861 Emily's family seem to have moved to Horton and there is another daughter Rosa, 7.
But in 1871 there's something really interesting:
George Bradford, 29, b. Windsor Berks, is living in Paddington with the following:
his wife Julia
his daughter Elizabeth
his unmarried sister Emelia, 26, b. Windsor
his unmarried brother-in-law, Robert Burton, brother of Julia.
a lodger, Andrew Anderson, 23, from Sweden.
I think "Emelia" may be Amelia Maria Bradford, b. 1843 in Windsor according to freebmd.
Freebmd also shows Anders Theador Anderson married in Kensington district to Amelia Bradford in late 1871.
I can't find these on the 1881 census, but I think it's quite likely they're the parents of Ada.
