Several issues already noted...
To me this looks like a (mostly) properly completed inspection followed by lack of judgement or experience leading to silly or inappropriate coding.
I assume the cooker rating is not actually a 6A but 32A or similar for a 6mm feed? R1+R2 looks a bit high for both shower and cooker in any case, but that could be down to poor connection where testing...
With the possibly exception of the outside light, which can't make much comment on without seeing it or further information, I don't think any of the other C2s are ones I would give...
Even the person from NAPIT found it hard to justify the C2 for all cables less than 50mm when confronted about it - I wonder if the inspector in this case actually verified whether any of the cables ARE less than that anyway, given the limitations...
This is where the problem with guidance comes in - NAPIT codebreakers book may suggest C2 for this, but the Best Practice Guide, which is specifically mentioned in the Government guide to PRS legislation states a clear C3, which is IMO a much more reasonable outlook.
I completely fail to see how missing labels can possibly constitute a C2 in any circumstances.
I think I'd even advise landlords to question in future when employing a inspector on which basis they plan to inspect, and consider very carefully whether they want to employ someone uses the Codebreakers book religiously.
This smacks of someone either looking for work, or going through a box ticking exercise rather than using any common sense in judging actual risk. The codes are after all supposed to be more based on risk than how closely they comply with regulations.
Though if the storage heaters were installed recently as I believe was stated it does raise the question of whether they were installed to regulations at the time...
Adding the RCBOs may have been unnecessary, but is at least an improvement to the safety of the installation. Though I'd still be interested to see how they certify them without rigging up a temporary supply to them...