Chris
I'm not so certain that you are correct about not being able to complete the night rating before applying for your EASA FCL licence. A number of schools are advertising the Night rating as part of the ab initio PPL course which, if correct, implies holding a pilots license is not necessary but only the relevant medical certificate. I can remember this being argued out some years ago but I can't remember the outcome.
Certainly, I have completed numerous night ratings for PPL students, during their ab initio training, in the past without issue.