Release PT
I think that what the CAA is saying is that, if you do not revalidate your MEP at the same time as your IR, you will not be allowed to excercise the privileges of the IR in a m/e aircraft because your MEP rating will have expired.
However, if you have revalidated the IR you will still have a current IR i.e, its expiry date will be one year on from its current expiry date.
There is no point in revalidating/renewing your MEP unless you actually want to fly a m/e aircraft. The airlines are only looking for a current IR, not a current MEP. You have to revalidate/renew your IR within 7 years of its expiry date, in order to keep your ATPL ground exam credits. Not renewing your MEP, even for more than 7 years, does not affect your ATPL credits.
The only extra thing you have to do if you let your MEP lapse for over five years is the MEP 40 question written test. So, to answer your question, on alternate years you can revalidate your IR in the FNPT2 and it keeps it current.
Linda Mollison