Probably not, but once qualified, the pilot can then exercise the privileges at Night solo, even if his visual acuity is such that he can't see a thing. The medical restriction that causes this problem is surely there for Safety.
Not necessarily - if the medical is restricted to day time only that won't change so not legal to fly at night P1 after gaining IR, but if you meet the requirements as suggested to gain NQ and then IMC/EIR or any other IR then you can fly IMC during daylight hours legally. At the moment you cannot fly day imc without a night rating which is not very logical as you can fly day vfr
So my suggested route is to tick some boxes on a bull**** requirement not to permit anything perceived as dangerouse.
To get anywhere with the illogical regs at present you need to play the authorities at their own game and point out the idiocy of some iof the requirements.
Believe me I know !!