I agree that if it is a C3 then it's only recommended, but the report that was produced said that it was a C2 on the Observations page, but on the Inspection schedule page shows it's a C3. Should it be C2 or C3, bearing in mind the consumer unit was installed when the flat was built in 2005?
As has been said, this has been much debated here (and elsewhere). The issues has always existed, but has come into much greater focus since July, when the legislation requiring inspections/reports (effectively EICRs, although the legislation itself does not use, or even mention, that term) for private rented premises came into force. Prior to that, EICRs had no 'teeth' - they were essentially just 'advisory' to the person who had commissioned it, who was free to ignore everything in it if they so wished.
I think it's probably fair to say that most people (including here) think that a plastic CU should not get a C3 - i.e. it should get C3 or nothing. However, none of this is 'dictated' or regulated and the problem is that the decision as to whether or not a non-compliance/conformity with the current regulations represents a 'potential risk which requires urgent remedial action' (i.e. C2) is down to the judgement/discretion of te individual inspector.
This is clearly totally unsatisfactory (akin to a 'postcode lottery', given that it depends on who does the inspection), and there's no obvious immediate solution (I think that some changes/extensions to or, at least, clarifications of, the legislation are ultimately going to be required - but that's no help now).
Both the legislation and associated guidance documents are rather unclear about this, but one option might be to discuss this with your LA, to indicate that you were unhappy with some aspects of the EICR and intended to have another done. If they were happy with that (rather than 'forcing you' to stick with the findings of the first EICR) then, albeit it would cost you another £192 or whatever (but a lot less than a new CU), you could then get another done - but, of course, only after first asking the person who was to do the second EICR about his/her approach to (coding of) a plastic CU!
I would add that although "smoke detectors have expired" is probably an issue you would want to address, I don't think it's actually within the scope of an EICR, witness the fact that (unlike the other things) there were not able to quote the number of a regulation in BS7671 which they claimed was being violated.
Kind Regards, John