Still unsure. Is OP the landlord or tenant of this property?
I don’t think reading the EICR is going to help…. They seem to have C2ed everything just to get an UNSATISFACTORY and force an awkward board change.
There has been suggestions on how rcbo’s can fit this board to satisfy some of it, but a non combustible cover for the board could be the sticky bit.
Fitting a new board on the surface is the only answer I can see…. That gives rcd protection where it’s needed, an SPD, non combustible materials…. Off the shelf components and straightforward. Only downside is the surface mounting.
Also, to clarify, you don’t need to use the same electrician that did the EICR to do the remedial work.
Although I did say it before, it’s unfair to suggest all electricians on mybuilder or whatever are unscrupulous… there are some good ones, I’m sure.
Word of mouth recommendations are possibly a better bet here. Are there any neighbours that have had work done recently that you could speak to for names?