It is not at all clear what the potential danger to life is - if an RCD was actually faulty and failed to trip on the day when the test button was pressed, then that's a C3 or a C2, depending on what role the RCD is providing.

Note  it is not a C1 unless when the button is pressed the cover falls off and exposes live metal to the touch .

Not being clear what the RCD protects due to absent labels maybe warrants a C3 as well, and a recommendation to re-label things I suppose 

 However, just "not able to find previous test results" is the normal condition on very many sites I suspect - On that basis the inspector must go around awarding C2s to everyone they visit.

As described it sounds to be something of a bit of a jobsworth matter

( i,e someone over enthusiastically (mis)using their modicum of authority in a way to make their role become more important than it really is, usually to the inconvenience and irritation of others)

.

Mike.

I agree, definitely no C1, failing to trip on button or >300mS with instrument test at 1xI∆n I would give a C2, but absence of evidence of biannual function test (common in domestic environments) or instrument test within 5 years (max recommended industrial EICR period) or missing labels is surely only a C3 at most.

Definition of C2 :-

C2 - Potentially dangerous - urgent remedial action required.
This means that this fault is not immediately dangerous in the same way as a C1 code is, but it could quickly become a hazard in the future.

Even if due to production constraints, they couldn’t test the RCD/RCBO, that does not indicate that it is potentially dangerous and need urgent remedial action.

It would surely have to be a C3 at most?

I agree, definitely no C1, failing to trip on button or >300mS with instrument test at 1xI∆n I would give a C2, but absence of evidence of biannual function test (common in domestic environments) or instrument test within 5 years (max recommended industrial EICR period) or missing labels is surely only a C3 at most.

Definition of C2 :-

C2 - Potentially dangerous - urgent remedial action required.
This means that this fault is not immediately dangerous in the same way as a C1 code is, but it could quickly become a hazard in the future.

Even if due to production constraints, they couldn’t test the RCD/RCBO, that does not indicate that it is potentially dangerous and need urgent remedial action.

It would surely have to be a C3 at most?