Hi,
I had a look at the 1881 census ref: RG11/318/31 p 6. It looks like these are the right people.
James Beasley, his Wife Elizabeth born abt 1854 in Bethnal Green, Middlesex, England, 3 children, James & Elizabeth born in Northamptonshire & Henry born in 1880 in Shoreditch.
If these are the right people it gives the Wife's name as Elizabeth as a starting point.
I hope this helps.
Cheers
Richard