Doesn't it?The ESC Guide (I'm sure the ECA would not like their considerable input to be attributed to the NICEIC), has taken the British Standard term 'requires improvement' and changed it to mean Unsatisfactory.
In ordinary English, if you said that something was required to be better than it was, you'd probably not be thinking that it was satisfactory...?
If I said that, it isn't what I would mean at all. It would seem that you would though.
Probably?? - in other words not definite.
I don't see a Plain English Crystal Mark attached to BS7671. It is a technical document and as such can not be considered to be 'ordinary' English as so many references, phrases, definitions could not be considered to be ordinary English.
Also, you have missed the meaning of Unsatisfactory. In PIR note 8 you will find the phrase 'overall satisfactory'. This is the same two words to which the Inspector is testifying at the bottom of the Report. So, overall satisfactory means that although some parts may be unsatisfactory, the installation is overall satisfatory. Therefore, the parts which are unsatisfactory, but which are not sufficient individually or collectively to warrant an overall unsatisfactory can be deemed to require improvement.