(2) in the case of applicants of an IRI(A) for multi-engine aeroplanes, meet the requirements of paragraphs FCL.915.CRI(a), FCL.930.CRI and FCL.935;
There is no IRA for multi-engine aeroplanes defined in the document! The IRI is not Class or Type specific.
FCL.905.IRI IRI — Privileges and conditions
(a) The privileges of an IRI are to instruct for the issue, revalidation and renewal of an IR on the appropriate aircraft category.
Therefore all it need say is what it said in JAR-FCL
(b) the issue of an IR(A) multi-engine
aeroplanes, provided that the instructor meets
the requirements of JAR-FCL 1.380(a).
The bit that was missed out.
As Part FCL says you need to be both an IRI and a CRI (ME) then that is what you require. As the training can only be conducted at an ATO they will check that you meet this requirement, elective training is not worth anything.
Have you already been conducting training at an ATO? If so, what does their Ops Manual say? If not, you could hardly claim grandfather rights!