Right your all getting confused with ratings
MEP multi engine piston
SEP single engine piston
IR-SPA-ME instrument rating -single pilot aircraft-multi engined.
IR-SPA-SE as above but single engine.
IR-SPA-ME qualifies you to fly SPA single engined aircraft.
To start your type rating you need IR-SPA-ME to be valid it doesn't to my knowledge require you to have a ME class rating active it could have changed though.
I have seen a couple of lads who have renewed thier IR-SPA-ME on the FNPT II in Leeds then jumped in a car down to Woodford to start their Jetstream rating the next day.