The night experience never expires, so apply for the QUALIFICATION (it's not a rating) any time.
The "CPL" is valid 12 months from test date - so is the IR.
The "Class Rating" (presumably MEP from reading your post) is 6 months. I have heard, however, from one CAA bunny that MEP class, if applies for as part of CPL skill test is 12 months - other bunnies say, 6 months (and I do know at least one that was rejected for being out of date.
Even the CAA don't know - so not much point in relying on LASORS for the answer to this one.