Hi Carol
I carnt see a Sarah Barker on the 1901 born Billington

there are four possibles
Sarah Eacott married to a William she was born 1873 ish
Sarah Hughes married to a Edward she was born 1871 ish
Sarah Rolls married to a Thomas she was born 1870 ish
Sarah Stevens married to a Charles she was born 1873 ish,
perhaps if she was working in London, she might have got married down there

ricky