with ELECSA the official line is this...
No RCD protection to socket circuits - Code 2
No RCD protection to lighting etc... Code 4
The big grey area with PIR's is how far back in the regs is deemed unsafe?? At the present time, is a house built 2 years ago and wired to the latest 16th edition regs deemed as unsafe?? The answer is, of course not and therefore any areas you find that do not comply with current 17th edition regs would be marked down as a code 4... However, if you go to an installation that was wired in accordance to 15th edition regs is it still unsafe? even if all testing shows its ok. I've asked this question many times to college lecturers and ELECSA inspectors and non of them seem to give the same answer.
At the end of the day, its the responsibility of the person carrying out the inspection, if you feel the instalaltion is unsafe, report it as such.