"The same is not true of the EASA IR, where 'some' of the training has to take place in EASA airspace, and the EASA IR skills test HAS to take place in EASA airspace."
That applies only to IR training courses conducted at training organisations approved in third countries. This won't apply in the case of Part-FCL appx 6, Aa.8 (ICAO IR + 50 PIC IFR ---> CBM-IR).
ORA.ATO.150 Training in third countries
When the ATO is approved to provide training for the instrument rating
(IR) in third countries:
(a) the training programme shall include acclimatisation flying in one
of the Member States before the IR skill test is taken; and
(b) the IR skill test shall be taken in one of the Member States.