The possible issue with this could that if the work carried out was not up to certification standards and material or life was lost before it was eventually certified, the person carrying out the work would most likely be sued and their professional indemnity insurance would most likely not cover them. That could happen now without the new regs, but with the new regs the certification should be carried out at the point of installation, not some indeterminate time later.
And what about a situation where some work was carried out and not certified, and someone else comes along and bodges a change from which loss results? If the initial changes weren't certified then the practitioner may well find himself facing a charge due to someone elses poor work. Again, could happen now.
I see some good in these new requirements in so far that if the standard 16th edition tests are carried out then the likelihood is that the installation is safe, and certificated as such.
The bit I do not like about these new regulations (and which I continue to badger government about) is the notion that you have to be NICEIC registered in order to prove you can write certificates. I'm going to college in the new year to do the C&G2391 course which will provide me with the knowledge to perform the tests. From that (and using the approved test equipment) I could most likely write valid certificates. But those certificates would be meaningless unless I were an NICEIC member.
This is like saying to someone that they have just passed their driving test but they aren't allowed on the road until they have gained their AA membership. The bit that government can't grasp is that NICEIC membership does not equate to improved safety.
PoP