My little one previously only had her father’s last name and I wasn’t asked for any permission or anything in the airport from her father. She now has a double barrelled last name, but we went before that changed xx
I have always taken a letter just incase for back up. I’ve been asked both times at immigration on the way back in and I just said he’s got dad’s surname and that was that. They didn’t ask to see letter or birth certificate x
I didn’t get asked for a letter however she only has my surname x