yes quite right but like you say it doesnt proove competence so, so long as youve filled all the paperwork out properly and covered your self by ticking all the right boxes etc then you are covered if it goes belly up, as you know that document is a legal document that you have signed stating the condition of said installation, if something went wrong then the effected party would surely try and proove incompetence but how can they do this when you have produced a proper pir report?
i do see what your saying but treat it like this, what if you filled a Domestic installion certificate out when not registered with a scheme provider etc? your still testing, siging and certifying that job, not much difference between legal impacts of either situation, just gotta make sure you state the extent of works covered etc. until someone says you have to have this qual to do this type of work then id just carry on as usual, think alot is down to each person and how they rate there own competence, i.e C&G electrical installation, time in the trade etc i have no doubt that i could carry out a pir resonably well but i would need to confirm Code numbers for things as im not that up on these, but that wouldn stop me from completing a PIR as i would find this informtion out via reference books etc.
rich