I'm a little confused... Your question references the Victorian-WWI era, but then you mention "wonderful medieval setting." Is this story supposed to be set in both the Victorian age and Medieval era (like time hopping back and forth between the two)? Because the medieval era is a good 500 years before from the Victorian era...

Anyway, I suggest you plug in the term "Irish diaspora" into Google Books and see what comes up. A lot of it will probably deal with Irish immigration to America during the 19th century, but you may find some other interesting tidbits that will be useful for answering your question.

Anecdotally, (and mods, please feel free to smack me for this) my Irish ancestors emigrated to Canada in the early 19th century. Ottawa in particular. This was pre-famine and pre-massive wave of Irish immigration to the States, so what compelled them to move to Canada from Northern Ireland was, near as my genealogical research can tell, less of a dire life-and-death situation than famine or war at that point in time. They more than likely came to Canada looking for the usual opportunities: Better employment outlook, better quality of life, cheaper land, etc.

I can't say that it would have been "the best place" for an Irish immigrant family to settle (it was basically the frontier in the middle of nowhere), but it wasn't the seething, roiling cesspool that New York was a few decades later, which is the more common theme in the Irish diaspora.