If someone at the PPL/IR group actually minuted such a libellous comment as "......the vast majority of IMC Instructors have never held an IMC let alone an IR", that displays ignorance as well as arrogance.
Nobody from PPL/IR has said this and nobody would because it isn't correct.
There is a story going around that there are still some (old) instructors around who started instructing in the days when a plain PPL (with an FI) could teach the PPL. Later, when the CPL was made mandatory for paid instructing, these people were grandfathered in, by getting a BCPL. There were some other changes in between. As this is a sort of "CPL", and since a UK CPL carries IMC Rating privileges, these people ended up with an IMCR and were able to teach it.
I don't know if the above is actually correct (it's many years before my time) but if so any such instructors would now be approaching retirement.
It's true that many or most IMCR instructors don't hold a current IR, but that's simply a result of the UK PPL training scene, which is made up mostly of ATP candidates who are "just passin' through" and doing some hour building while thumbing through airline adverts. These people do have to get an IR eventually but many/most of those that do get it let it lapse while building hours because there is no point in spending £hundreds on renewing something that you don't actually need.
Anyway, if IMCR training was a safety hazard, we would see this in the accident data, but there is no support for this suggestion. And if there was, the way to approach it would be to do something about the training, not to abolish this very useful and accessible rating.