Gibraltarian players in non league

Hi,

First off, love FM17.

Second off. I signed an 18 year old Gibraltar player called Jayce Olivero for my Lincoln City save. It's the first season so I'm in the Vanarama National but he's ineligible for my first, U23 and U18 teams.

I can't see it saying anywhere why he can't play. I know they have odd rules for internationals in Gibraltar so is it something similar?

Ta