Hello harj. There are a lot of misconceptions listed on that report. I can give you my honest opinion but without the benefit of seeing the installation can only make observations.
1. Table 54.8 Main bonding is 10mm2 for when the PEN is less than 35mm2 csa and the earthing type is PME. For TT systems it can be less.
2 As above.
4 Limited access to a switch is not potentially dangerous. It should be recommended that the switch is made accessible. C3.
5 Landing switch fitted behind architrave. If there is no other explanation I cannot see how it is C2 either. No code required.
6 If there is a big hole in the TOP of the CU then yes it is a C2 if the exposed conductive parts can be touched. 416.2.2 The TOP of an enclosure should be IP4X, or IPXXD.
7. Consumer Unit not fire rated. This is rubbish. There is only a requirement to have a metal 18th edition compliant CU if it is installed on or after 1st January 2019. If the current CU is in all other respects adequate and compliant then he should NOT be giving misleading advice. There is, and never has been, any requirement to update anything to the latest edition of the Regulations. Too many electricians try this on.
8 No SPD. Again it is NOT a requirement to have one and certainly not if the CU was installed before 1 January 2019. There is a calculation in the Regs to assess the need. It is very unlikely it would show you do.
9 Mains tails too small. If they are 16mm2 the main cut-out should be 60A rated. If there is a 100A main cut-out the main tails should be 25mm2. These are the cables that sit between you electricity meter and the CU. If your CU was changed then almost certainly they would be fine as they would have been changed at the same time.
15 No earth on lights. If what he is referring to is no cpc in the lighting circuit it is daft to say the screw heads need to be covered. What it effectively means is if you have no cpc in the lighting circuits there should be no metal switch plates or no metal light fittings (Class 1) that would require an earth. You can have metal Class 2 light fittings they don't require an earth. Metal screw fixings on the accessories are not required to be covered. The only solution long term is have the lighting circuits rewired. This guy appears to have misconceptions and misunderstandings. It sounds like he is not experienced enough to be carrying out EICRs. My advice. Disregard his report and get someone else in who knows what they are doing.

Probably not what you wanted to hear. It is disappointing to see poor reports.

Point 1 - 10 mm is absolutely fine
Point 2 - if water service is plastic coming in then no bond required ( it’s a bond not an earth!). If it’s metal and you’re on a PME earthing arrangement then 10 mm is minimum required
Point 4- should be a fi or a limitation.
Can’t code it c2 if he can’t test it ??
Point 5- utter nonsense no code or observation
Point6- if you can push a 2 mm probe into board through a hole than yes it’s a c2. Easily fixed with a length of plastic trunking.
Point 7-utter nonsense. Regs aren’t retrospective. C3 improvement recommended at worst
Point 8- again a load of tosh. Recommended on new installation unless risk assessment says otherwise. Most good sparks fit them as standard anyway. Again c 3 at worst.
Point 9. These are the cables running from your meter/ isolator to your consumer unit. Difficult to say without knowing your supply fuse size and earthing arrangement. But I doubt they are undersized. An ill experienced sparks thinking 25 mm must be used. Ask for his calculation method for determining size, or the ref number which is deviating from
Point 15- c2 could be reasonable for this. But you could sort it yourself for a tenner Buy caps, push them in.
Think you have a recently qualified “ inspector” or worse still unqualified. Inspector should hold city and guilds 2391 or 2394/5. Other qualifications such as NAPIT testing is complete waste of time and only recognised by themselves. Go NICEIC APPROVED CONTRACTOR
B Whitby agree I know some great NAPIT sparks but also know some 5 week wonders that sit the NAPIT open book testing course and become “ qualified” inspectors. NICEIC AC scheme prevents this by only offering testing status to properly qualified inspectors

Agree with Jon Bateson on this. I think someone has tried to have your pants down. Either that or they are under qualified.
I don't agree with the NICEIC part though. I've been qualified for 6 years and I'm still registered with NAPIT, not all sparks are bad ones.

奇妙的芒不幸的是米有票价any people giving poor EICR tests. The only posible thing I would add to the metal cu debat is that there should be no signs of overheating in a plastic cu. If there are then it would need to be replaced with a metallic one or coded to reflect this.