Here is another family to consider:
1901 census, Rowley St, Deptford North
Parents James DAY (47, dock labourer) and Mary (45) both born Deptford
Children (all born Deptford) Amelia 20, Georgina 17, Henry 13, Mary 11, Alfred 8
Same family in 1891 census but the wife/ mother is named Margaret here.
Other children in this census: Margery 14 and Rose 9
Added; In 1881 census, she is also named Margaret.