After having read your post I would sayUKBA have picked up on the fact that your friend moved to Belfast and worked. A southern irelandresidence card does not allow u to work in northern Ireland which is UK.

Hey there, I have Irish citizenship through my wife. We live in the north. U do not need a southern Ireland residence permit to apply for Irish naturalisation. As long as u have been married for at least three yearsand u said u been in Belfast for 4 years now. You are well within the limits for appl...