INNflight,
As I understand it you have a JAA CPL MEIR.
The IR is valid for 12 months and must be revalidated via a test flight each year, you can alternate each year from a check flight in the sim and the following year it must be in an aircraft.
The MEP is also valid for 1 year and most people will revalidate both the MEP and the IR at the same time, however the MEP check flight can only be performed in the aircraft, not the sim.
Hope that help and sorry can't quote you the actual JAR FCL section.