[@Morose] The cost of travel alone is the big issue. You are looking a lot, more than she makes in a year just for bare minimal. She'd have to take a ship from Ireland to England first and then travel across land. Even today if she went by "horse and buggy" with today's ferries you are looking at 11 days. Back then with the roads being in horrible condition, the high level of Highway men, and more - If, and that is a big if, she got there alive, you are looking at a months travel. (Which she would have to start out in Dublin in the IC and move in time with the RP since her CS has her living in Dublin)

As to why, why would she go? London is a slum with smaller areas for the rich (Which the rich only come for the season and leave quickly because of the smell that covers the place.), they have cast off the Catholic Church, Irish gangs wouldn't cross into England's turf with the political issues, plus with the Soulless stuff - London has always had a problem - it would be far more dangerous a location for her daughter than Dublin. (no family, no safety net, etc)