I changed my consumer unit as the old one had rewirable fuses and no RCD. I decided the extra cost of having all RCBOs was well worth while as a fault on one circuit does not take out half the house.
There is another thread where this is being talked about, I also decided to fit all RCBO so less likely to loose essential circuits, then found the RCBO is type AC not type A, so there is some debate.
Be it plastic CU, not all RCD protected, type AC instead of type A or anything else one needs to assess the risk, so a plastic CU under wooden stairs is a greater risk than same CU in the kitchen. And even under the stairs if there is another escape route it's not as bad as if there is not, and swapping a CU to metal is rather pointless if the DNO stuff is still plastic.
So we need to assess the risk, and the big question is if the electrician is qualified to assess the risk? Building regulations are divided into parts, Part P covers electric, Part B is fire, Part F is ventilation, and there is some over lap, so with an open flue then you have to consider if a tumble drier or kitchen/bathroom fan can draw in fumes. And it may be considered it needs a CO2 detector to guard against this, but the big question is if the electrician is qualified to assess these risks?
So if you get a fire inspection and the guy says you need abc then OK, but the electrician is not trained in fire prevention or ventilation so it is wrong for him to be asked to do that risk assessment.
It is OK to say new CU should be metal, or new RCD should be type A, or new extractor should be heat recovery type, but as to recommending an upgrade if it was OK when fitted why is it not OK now? With some items maybe you can answer that, when the type AC RCD was fitted the house did not have an inverter drive washing machine. OK good reason for change maybe, but I have seen many an EICR done and that is all they have done, which to my mind is silly, if there is a bit of earth sleeving missing the action should be to fit some, not just note on a bit of paper, and if all the terminals in the CU are torqued up, then little chance of fire, looking at the terminals does nothing, they need testing with torque wrench or at least a screwdriver, there is a reason for maintenance free terminals, this is they don't work loose, so clearly if not maintenance free they may work loose over time so need checking, we called the EICR a service, and only major items would need reporting, small items were corrected as we went around.
I would say unless under wooden stairs that CU is no problem. But an EICR is a professional opinion, and the person doing it needs professional indemnity insurance, and to give advice on areas where the person is not trained will likely invalidate the insurance. I do know an electrician who is also a fireman, and is also trained in other aspects of health and safety, but most are not. I personally feel the details of insurance should be on the EICR, but never seen that done.
But we can neither say the guy is right or wrong, it's his professional opinion, all we can say is was he qualified to give that professional opinion?