My Mary Mitchell was born in 1861 in Mohill, Co Leitrim and married an Englishman on 26th Oct 1881 in Weymouth England and died in Camberwell South London in 1921. I am pretty certain she never visited Ireland after leaving. The only other thing I know about her is that her father was James Mitchell a "shoeing blacksmith".
Given the small population of Co Leitrim there is probably a connection between our Mitchells but its not obvious so far! Actually looking on the map, Dromahair and Mohill are at opposite ends of the county but even so there are not that many Mitchells.
Let me know if any more clues turn up.