As has rightly been said, anybody with the necessary knowledge, experience and skill can carry out PIRs. But, as PIRs are not within the scope of Part P, which governs installation
work, the NICEIC elected to not make their logoed PIR certs available for persons enrolled only under their Domestic Installer scheme.
Their original expectation was that qualified electricians would opt to become full Approved Contractors, while other trades would go for defined competence Domestic Installer.
However, the other schemes involved have served to muddy the waters in this and other areas, so a lot of people are understandably confused. One thing that has become apparent is that many one-man band electricians have elected to enroll only as DIs because this covers all their work. Not many small electrical firms have got heavily involved with testing (in fact - and you know who you are - a lot didn't even own test equipment until Part P!) Up to now.
Since the Housing Act 2004 came into force this April the NICEIC have been aggressively marketing towards landlords and in particular have been pushing the Domestic Installer, rather than the Approved Contractor logo. As landlords have an increased responsibility towards their tenants, it makes sense to allow suitably qualified DIs to carry out PIRs and issue reports with logos.
I'm still not certain how a customer goes about telling one from another though: NAPIT also has defined scope membership, so a NAPIT Part P Registered Installer could be anything from a kitchen fitter to a highly experienced all-round electrician in just the same way a NICEIC Domestic Installer could.
Me? I'm knocking on a bit, so I intend to get all the testing and inspection work I can lay my hands on!