I am neither instrumented rated nor based in the UK, so don't keep up to speed on this sort of stuff! But have the CAA issued some sort of reminder about the equipment required for IFR flight in their airspace?
If they haven't, this, combined with a notice of intention to check and prosecute, would seem like a much better way of making their point, than simply picking on someone at random and throwing the book at them.
As you say, no one seems to know anything about this, just heard the rumour. How long will it take to come to court? How long to actually get a final decision by the court? Surely a published reminder, and statement of intent would have a much speedier and widespread effect?
There seems to be a lot of people out there who like to bash the Cirrus, and I can only guess why. But in the light of that, I'd be inclined to disregard rumours, as just that, until we know something for a fact. I imagine a lot of people would feel the same way. So once again, it would seem to make far more sense for the CAA to make a statement, rather than simply pick someone to prosecute.
On the other hand, Cirrus's competitors might have an interest in spreading a rumour though, and this may be all that this story is?
dp