You haven't given any details of where he was born
William Elliott married Sarah Jane Jones 30/05/1896
I have only be able to go back as far as 1891 in the census which shows he's married to Sarah and they have 2 children
Is that a different Sarah than the one he married in 1896?
If so - have you checked freebmd for a likely marriage based on a couple of years before the first child was born?
A copy of one of the childrens birth certs will give her maiden name
EDIT
Is this the 1891 entry you are referring to? If so - is there a reason why you have posted on the Lancashire board as there does not seem to be any connection to Lancs
William Elliott 28 b Southwark London
Sarah J 24 b Dawley Shropshire
Ethel M E 2 b Birmingham
Willard 1 b Aston