I have managed to get the save to work.
My problem is now a stranger one: I have some pilots' Friendship missions unlocked, but no matter how much I play them they won't level up to 5 manually, they're eternally stuck at level 4.
I've tried modding their level with the Editor back to level 1, and after a mission I play they go back to level 4 again.
I've seen this happening in Amuro, Char, Ramba Ral, Milliardo, Heero, Jerid, Puru, Loran, Duo, Kai, Uso, Glemy and Schwarz. Everyone else I have mostly unlocked manually, or am in the process (I'm missing Haman, Roux, Yazan, Hayato, M'Quve, Sarah, Four, Katejina, Sochie, Beecha and Elle but I don't have their missions unlocked yet.)
Help with this please? I don't have the save right now but I'll edit this post soon as I retrieve it (different computer at the moment).
EDIT: Here's the save.
DWGUNDAM3