Essentially, holding a valid MP IR prevents the 7 or 5 year rules applying to your SP IR privileges however; you have to renew it as it has expired.
Reading EASA, there doesn't sem to be a difference now between the MPA and SPA IR?
The differences can be found in App 8 to Reg 1178 which lists cross credits
Appendix 8
Cross-crediting of the IR part of a class or type rating proficiency check
A. Aeroplanes