flyingfemme
Interestingly, I have an email from the CAA confirming that the IMC Rating is not restricted to a G-reg plane.
There is a proviso: that the country of aircraft registration does not object. The FAA, for example, requires that an N-reg plane is flown with an FAA license/ratings.
I disagree with your apparent view of the IMC Rating; for private flight in the UK, in a non-deiced piston engined plane it comes very close to a full IR in practice. The difference in currency between different pilots, and the sort of plane and kit in it, counts for far more than the difference between the IMC and the IR.
All PPL students who look like they want to get into it properly ought to be encouraged to to the IMC Rating as a necessary step for UK flight. 15hrs min, perhaps 25hrs on average to cover the necessary bits. I suppose the problem is that the school would risk losing business because doing so would inflate the apparent cost of learning to fly.