The installation certificate can only be completed by persons doing the work, but an electrical installation condition report (EICR) is a very similar form, so often that form is used to report to the LABC although not waiting until the end of the job, it is done at stages through the work. The electrician is selected by the LABC, but you pay for their work, sometimes one is given a selection of approved inspectors/testers, but one can't select any electrician who is a scheme member, as the work is not covered by most scheme memberships.
In Wales, third party inspection is not permitted, in England the law allows it, but to find someone with the scheme membership required is near impossible, as most of the schemes will not permit it, so may be theoretically possible, but in practice unlikely.
My son and I worked in Flintshire, Cheshire, and Liverpool, and the way the LABC worked was very different, Liverpool could not have been more helpful, Flintshire were really a pain, but remember my son and I are both electricians, although commercial not house bashing.
The meters cost around £70 a week to hire, since they need recalibrating after each hire, can't normally hire for less than a week, and the longer hired for, the lower the cost per week. To learn how to inspect and test, I did a course 3 hours per week, for 12 weeks, in fact did 3 courses one after the other, 16th edition as it was then, PAT testing (really called the inspection and testing of in-service electrical equipment) and the C&G 2391 which is inspection and testing of the installation. Back then it was cheap, around £100, now far more expensive, and collages don't want fails, as it affects their rating, so some will only allow electricians on the course.
The LABC is responsible for site safety, so they need to do a risk assessment, which includes assessing your skill, technically maybe they can't refuse, but they can charge each time their selected electrician visits, and this may mean it will cost more to DIY than to get a scheme electrician to do the work. This is down to your LABC, as said some are great, and others are not so helpful. It is so long ago when I did it, not a clue what they would be like now.
Here in Powis, I can go on the council website and view all registered work done on my house, so no way to hide work, but Flintshire seem to be in disarray and work I know was registered does not appear on their website, so it would be hard to show illegal work had been done.
What I did with late mother's old house, was got an electrical firm to do the basic rewire, then I added to it as required latter, doing work which did not require registering. I looked at the paperwork when I sold the house, and there were three lots of work done, and nothing to really say what work had been done by whom, so the paperwork was in real terms useless.
