Hold a valid IR(R) and an unrestricted FI rating;]
This is a rather outdated concept going back to National ratings.
To teach for the IMC or IR a FI must have embedded IRI privileges, this is indicated in section XII of the licence under FI with a (g) for the IR and (g)(IRR) for the IMC-IRR simply holding an IR is not enough.
Completed at least 10 hours flight time by sole reference to instruments in an aeroplane
This is a prerequisite to undertake a FI Course FCL.915.FI.FI. You must also hold a UK issued licence to teach for the IRR as it is an exclusive UK rating.