Having seen the pictures I concur it certainly is untidy...or as a tradesman would say rough. I would say there are a few things that we could probably point too as areas for attention. Nothing life threatening but I would be giving Napit a call if the electrician does not provide you with a satisfactory job. Personally I don't like the way the cables are just slung in and also the routing around the copper pipe is...."interesting". I don't know weather you should be worried...but if this is the "best" part of the install then it certainly does not look great.
On balance I think my advice would be to get an independent report done by another electrician. I know this may cost you another £150 or even more depending on the size of the installation needing checked...But for that you should then be armed with a report listing the faults that need rectifying if any. As said maybe NAPIT would send someone out from their own list to check it over so no need for you to pay for another independent electrician.
I suppose it all depends on if you are still willing to let the electrician involved to rectify any issues...if the relationship has broken down then you can only call NAPIT - email them those pictures if the facility allows. Maybe someone on here who is with NAPIT knows more of their procedures.
Also could you try to get a better shot/picture of circuit 1 on the right (Cooker) - the red cable seems an odd color. At first glance it even looks like VIR.....which if it is needs replacing.