I can only guess Sarah added a few years for impression. Martha may be Maretta born 1848 but christened in Liverpool 1849 she used Maretta in 1861. Henry 1844 appears to be christened with the second Walter in 1851 but this Walter also died young.

There was another John and Sarah Morrison family in Liverpool 1851 so IGI may be showing their children.

Len Faragher