Easa part fcl 720 states
(d) Multi-pilot aeroplanes. An applicant for the first type rating course for a multi-pilot aeroplane shall be a student pilot currently undergoing training on an MPL training course or comply with the following requirements:
(1) have at least 70 hours of flight experience as PIC on aeroplanes;
(2) hold a multi-engine IR(A);
(3) have passed the ATPL(A) theoretical knowledge examinations in accordance with this Part;
and
(4) except when the type rating course is combined with an MCC course:
(i) hold a certificate of satisfactory completion of an MCC course in aeroplanes
which would suggest you only need the IR to be current to start the type rating course, it can expire before completion and application. The MEP isn't relevant at all.