I have not heard of the "safety pilot" route. I suspect you already know the following, but:
Among other things, you need: "5 Take-off and full stop landings at night as PIC of aeroplanes" (LASORS E4.2c) for the Night Qualification. Legally, who could your non-PIC passenger be, before you have the NQ?
And, for reasons I never began to understand, you definitely do need an NQ before you can even start IR flight training (LASORS E1.2). The CAA confirmed this to me in writing last year.
Good luck in your search for a way. Why is a day-restricted IR not permitted? I believe there are day-restricted CPLs.