I am not sure that is correct.
The CAA will approve an EASA Examiner to conduct an IMC revalidation. I did mine in Spain 3 years ago. So training would be even less of a problem I would have thought.
Another example of the ineptitude of the CAA who neither understand nor comply with their own rules
IN2016-082
4 Instructors Wishing to Teach for the IMC Rating/IR(R)
4.1 Commission Regulation No. 1178/2011, Article 4 (d) requires that the CAA specifies credits that are to be permitted in relation to Part-FCL Annex I requirements for those wishing to instruct for the IMC Rating/IR(R).
4.2 Part-FCL Annex I states which instructor certificates are required to teach for the Instrument Rating (IR(A)). On that basis, the following will be considered competent to deliver instruction for the IMC Rating/IR(R):
a) The holder of a valid Part-FCL Flight Instructor Certificate
issued by the UK CAA who can teach for the Instrument Rating (where FCL.905.FI(g) is endorsed within their licence); or
b) The holder of a valid Part-FCL Instrument Rating Instructor Certificate issued by the UK CAA.
The instructors must also hold the appropriate aeroplane class or type rating.
5.2 Only examiners who hold licences, ratings and certificates issued by the UK CAA may examine for the IMC Rating/IR(R).
Quite clear to anyone who can read, if they know where to look!