I've just seen this message - sorry I'm late in replying. My Elizabeth married James Cavanagh (should be Kavanagh) in 1872 in Birkenhead. They were both born in Ireland but married in Birkenhead. They are in the 1881 census with 4 children - eldest born in 1873.
I will order the marriage certificate as it will help I know. I have the birth certificate for their son William who became my grandfather. I found in Roots Ireland an Elizabeth Smyth born in 1848 in Co.Offaly (used to be Kings.Co.) showing a Thomas Smyth as the father Sally Neill as the mother. Spellings did change so will await the arrival of the marriage certificate. Thanks for your help. Angela