He's a pain in the ****ing bollocks. Went for lunch today and ended up costing me a ton or there abouts on a Tracksuit and a T shirt.
It's not important Ciaran really, they just want to limit the number of minors travelling, especially if not with a guardian. Under 16 flight should be a small bit cheaper also. Make sure you say they are under 16, which is a fact as you said they will be 15 when flying out. After that it doesn't matter one bit as long as they have their passport on the way back have a great holiday m8.
I think they are trying to restrict minors travelling alone as it creates added pressure on airline companies. Just a guess.