Despite every wildcard system I can think of, I haven't been able to find my great grandmother on the 1901 census. Either there's a mis-spell of her name or every index I've searched has picked her name up incorrectly.
Her name is Ellen Thorogood and in 1901 she would have been 17. She was born in Rush Green, Romford and is definitely not with her family so I presume she is in service somewhere.
She married in 1904 in Horndon on the Hill, so I don't think she'd have strayed out of Essex in 1901.
Hopefully someone else will find her name somewhere.