The CRI rating was slow to get started, simply because it was put there as the new JAA equivalent to the National TRI(SPA). At exactly the same time the JAA removed the requirement for SP "Type ratings" formerly needed on every different type of aircraft (Yes, every FI conducting professional training had to have a separate Type Rating for each aircraft type they taught on)
At the same time, CAA management, without any reference to its technical licensing staffs, produced a back door agreement giving a number of pilots "instructional privileges" these included BGA Tug pilots and LAA coaches. Ironically, some of these were even given approval to be paid whilst a PPL FI could not! At some point to cement over this "old boy" activity, all such "GIZIT" "instructors" were given a CRI rating free gratis, having never received any training or testing. Many of them were even too lazy to follow the revalidation procedure (a free sign off by a FIE) and went en-mass to the CAA expecting them to do it for them. Some had expired, but they were charged £75 a head and given another "GIZIT" CRI without meeting the renewal requirements.
I recall one Microlight FIC instructor saying to me, "I have just run a Microlight FI course for an aeroplane CRI, how the hell did he qualify?" Clearly he didn't and the day of reckoning is nigh.
Not only is there no defined standard for the CRI test, there has never even been a syllabus of training for a CRI(SE). The JAA never produced one so there was nothing for EASA to copy and the EASA AMC 900 page Compendium of Crap contains nothing. The initial CRI Courses included 60 hours groundschool, until a JAA amendment gave rise to some doubt over the actual requirement which was and still is not clear.
The resulting AIC still exists.