In the 1891 census, Pheobe is with her grandparents in Northop (Charles and Margaret).
Also, there is another grandchild, Maggie, aged 5, born Northop.
Also, in the 1901 census, Charles and Margaret have a grandson, William, aged 5, b. Northop, staying with them.
Have you checked the birth records of Maggie and William?
Gadget