The forms in PDF format can be down loaded
here and there is some instruction with them.
The big thing is anyone doing a PIR is giving a professional opinion and often normal public liberality insurance will not cover and they need professional indemnity insurance. I don't know of a case where an electrician has been taken to court after completing a PIR but I have seen PIR's completed with a lot to be desired. In the main the selecting of code 1 or code 2 and many items that following the rules should be code 2 and given code 1. There is also the code 4 which if we look at the first edition near every fault could be given a code 4 as it did comply with that basic document and really one should only go back one book so anything not in the BS7671:2001 but in BS7671:2008 would get code 4 but earlier than BS7671:2001 would be code 2.
However the guidance given by the Electrical safety council as to coding is not worded that way. However see
here it is "Does not comply with current Edition of BS7671" so even for items like no earth on a lighting circuit an electrician could consider as not required pre-1966 this could be code 4. Unlikely but it does mean the code system is not much good.
The description is far more important and one should really go through the report with the electrician to clarify any points. However with large firms the electrician enters details on his PDA and they are sent to main office for typing and are posted out to client who may not be the occupant of the building and by time anyone queries any points the electrician has completed another 30 PIR's and can't really remember the details so the repair electrician has to work it out for himself.
Hence next year same fault found and maintenance electrician has repaired a completely different fault.
Of course not giving good details helps the PIR electrician as if something goes wrong he can say it was that fault he had identified even when it was in fact something completely different. I have never completed a PIR giving a clean bill of health. There is always something found.
The idea of not showing the previous PIR to new guy does not work either as to begin with it is a requirement so the new guy can assess any deterioration and second no one is perfect and it is expected that there will be different opinions. Hence type of insurance.
Having said that most faults found are cut and dried and lack of an earth cable to broken socket is normally going to be reported in same way with most electricians. But it is his opinion and one electrician may code it as 1 and another as 2 and neither is wrong.