Marrying an overstayer

[Andre76]

I am british man living in england and have been in a relationship for 6 years with a girl that has overstayed her visa by a few years. We would like to marry but i know for any chance of that she would have to voluntarily go back to her own country first as we couldnt get married in england without home office getting involved and probably deporting her.

My question is i have irish and an english passport so is there anyway of going to ireland getting married then coming back without anyone getting arrested or deported?

[CR001]

What is her nationality?

Would she normally require a visa to visit Ireland??

Ireland and the UK share immigration data with each other.