I live in NI and have daughters who regularly fly over to stay with me, going back over 7 years.
Each time they visit, I called RSA and asked to add one or other. The first occasion they spoke to my daughters and got full details including licence and added for a specific period, normally days. Second and subsequent times they just required the name of which daughter was being added and if any convictions since last contact.
On every occasion I received a letter confirming that the additional driver and dates for my records.