So, in 1891 there's an absolute hoard of them living at 67 Thesiger St, Caistor, Lincs, mother born Bilston, second youngest sister born Grimsby, everyone else born Wolverhampton. Given the way the offspring are listed, with two 11yo girls born in different places, I'm suspecting a "combined" family maybe.
Possible births are:
DAVIS, ADA MANDER GRO Reference: 1881 S Quarter in WOLVERHAMPTON Vol 06B Page 609DAVIS, ADA EVANS GRO Reference: 1881 D Quarter in WOLVERHAMPTON Vol 06B Page 519
Looking for a marriage between James Davis and Mary A. Mander or Evans, probably in Wolverhampton or Bilston we have:
JAMES DAVIS Q3 1870 born 1849 married Mary Ann Evans born 1848, Wolverhampton Staffordshire Vol 6B Page 656
Also: 17 Jul 1870, Father George Davis, Spouse's father Herbert Evans
Possible children:
James, 1871 M Quarter in WOLVERHAMPTON Volume 06B Page 519
Herbert, 1872 J Quarter in WOLVERHAMPTON Volume 06B Page 512
Elizabeth Jane, 1873 D Quarter in WOLVERHAMPTON Volume 06B Page 501
John, 1874 M Quarter in WOLVERHAMPTON Volume 06B Page 665
George William, 1875 J Quarter in WOLVERHAMPTON Volume 06B Page 535
Joseph, 1876 J Quarter in WOLVERHAMPTON Volume 06B Page 700
Alfred, 1877 S Quarter in WOLVERHAMPTON Volume 06B Page 543
Alfred Thomas, 1878 D Quarter in WOLVERHAMPTON Volume 06B Page 648
Mary Ann, 1879 D Quarter in WOLVERHAMPTON Volume 06B Page 564
Ada, 1881 D Quarter in WOLVERHAMPTON Volume 06B Page 519
Ethel Georgina, 1885 J Quarter in WOLVERHAMPTON Volume 06B Page 542
There were others but the "fit" wasn't good enough for the 1891 household. There are still a couple of anomalies for you to sort out via the 1881 census, and I'm not sure who Eva is on the 1891, but from searching the GRO index she doesn't appear to be a Davis nor yet an Evans born in either Grimsby or Wolverhampton.
Next, Ada's marriage:
ADA DAVIS and William A Andrew, Grimsby Lincs, Q3 1911, Volume 7A Page 1427
And their possible children:
ANDREW, MARJORIE, DAVIS, 1912 D Quarter, GRIMSBY Volume 07A Page 1069
ANDREW, WILLIAM JAMES, DAVIS, 1914 M Quarter, GRIMSBY Volume 07A Page 1155
Also this, but the age at death is wrong .. unless it is a typo for 6mo ...
ANDREW, WILLIAM JAMES age 6, 1914 S Quarter in GRIMSBY Volume 07A Page 633
I've drawn a blank on the 1939 Register, but here are links for the Kesteven assylum near Sleaford (not far from Boston) and the one nearer Lincoln:
http://www.genuki.org.uk/big/eng/LIN/Rauceby/rauceby_asylumhttp://www.genuki.org.uk/big/eng/LIN/poorasylumhttp://discovery.nationalarchives.gov.uk/details/rd/fec1239f-8422-49b6-83af-cb2b5147edceThis lot should keep you out of mischief for a bit!
Stitch