If your IR has not passed its expiry date you can revalidate it in an FNPT2 without having to renew your MEP (which you have to do in an aircraft).
If the only reason you are revalidating your IR is to keep it current whilst you look for an airline job, you do not need to renew your MEP.
If you plan to use the privileges of your IR in an MEP aircraft, you must also revalidate/renew your MEP in an aircraft, although you can still revalidate your IR in the FNPT2.
If your IR has passed its expiry date you must renew it in an aircraft.
If you are renewing your IR in an aircraft it is probably worthwhile renewing your MEP at the same time (in fact your FTO may insist on this).
If you have done no MEP/IR flying since your initial IRT it is unlikely that you will be able to revalidate/renew either your IR or your MEP without at least one training flight first.
Linda Mollison