You need to attend FI refresher training at an ATO, formerly called a Seminar and to pass an assessment of competence with an FIE. To do the latter may require training as required with an FIC instructor.
To add the MEIR part you will need to have completed the CRI (ME) course and the IRI Course. Whilst you are still a FI(R), you will need 800 hours IFR to undertake the IRI Course but as an ex airline pilot that should not pose a problem.