Because I did my IR first i had to find out about this and it does matter which order you do things in.
Before issue of CPL you need to have done only the training for night but not have it added to your license. (the same with the MEP trainng if your doing it in the twin)
Then as someone says if you hold a valid pass for CPL but not issued you only need to do the 50hr course for IR. If you did the CPL in a twin you don't need a stand alone MEP skills test pass.
If you then go on to FI you only need the CPL requirements for FI.
But if you do the IR first you need the night actually issued on your PPL ( paying the fee) and do the 55hr course. But you have to have done the training for the MEP and hold a valid skills test pass (but not issued). This is in theory because the caafu never seemed to bothered if I had already passed the MEP skills test yet and I presume that GAtwick wouldn't let you book the test if you didn't comply with the night rating stuff.
CPL you then get for the reduced course length 15hrs I think.
And again you get the reduced PIC time for the FI.
Then you send the whole lot off at once you only get stung for CPL/IR MEP issue and adding the FI rating. And your MEP pass is taken from your CPL skills test not the original skills test date if done in a twin.
MJ