Whoever ordered the work should contact the NIC as this is quite wrong.
A PIR does what it says on the tin.....it's a report. It does not cover any work, see the guidance notes on the report itself!!
Then there's installing a 16th ed cu 3 years after 17th came out! I'm assuming you mean that lights etc have not been rcd'd despite buried cables.
Then they clearly didn't I&T properly if they've quoted a 1mm cpc (amd presumably an R1+R2 or Zs) when in fact there is none. That's basic.
Add in not understanding the certification requirements. Again, basic.