Hi Nicola,
I think I have found Nellie in the 1901 Census.
She has been transcribed as Nellie William, aged 12 however if you look at the actual image it is Nellie Williams aged 16 born Branstone Staffordshire.
1901 Census Piece - 2642, Folio - 150, Page Number - 11
40 New Street, Burton On Trent Staffordshire.
She is a Domestic Servant in the House of Joseph Smith, a Butcher.
Spendlove