I doesn't take rocket science to wire up a house, compared to a lot of building jobs, it's pretty damn simple. When i used to work on building sites, 80% of electricians work would be done by unskilled Labourers. And then the sparky would come along and inspect/test it all. Labourers would do most of the wiring, but leave the sockets and switches loose for easy inspection.
It is not the science which is in question, it is who can sign to say it is OK, that is and has been for many years the person in control, so if you got an electrician to employ you to do the donkey work for him, he is in control, however if you decide to do something he has not sanctioned they he must be free to make you do it again and do it correctly, be it plastering up a wall before he has inspected, or some thing more serious. When I got into the position of electrical engineer I realised how much calculations mattered, OK as you say not that hard, I used on line calculators for some things. However before laying a cable, you do need to know what volt drop and what loop impedance will likely be measured. The last thing you want is after wiring to find it does not pass.
Building Regs in my area don't seem very interested. There are people in my area who's whole roof structural is structurally inadequate / dangerous, yet building regs never inspect. I studied structural engineering.
I also found the LABC did not seem to be interested, however that does not really help, I would prefer some one to say sorry you can't do that, to landing up in court in 5 years time. Reading court cases you quickly realise the LABC seem to have a get out of jail free card. One simple question, have you the skill and if you say yes and you have not got the skill then your fault. Only if you do something blatant to show you don't have the skill are they in trouble.
But read
The Emma Shaw case and you see how often it's not who you expect who gets the blame. But one thing which will happen, is every bit of paperwork will be checked. You can try as many tricks as you like, but if anyone goes to hospital and is given just one day off work, then they will look at what went wrong. I have had the HSE inspecting my work, lucky they found nothing wrong, but Dec 2007 to March 2014 for the Emma Shaw case is a long time to not know if your going to be found guilty or not. Once the HSE get their teeth into something they will not let go.
I got very worried about volt drop, I realised for years I was considering 1.44Ω with a ring final was a pass, for the MCB to trip this was correct, however 0.94Ω is the pass mark for a ring final where the incoming is 0.35Ω it was not until a lecture I attended by the IET when it was stated we were now allowed 106 meters of cable in the ring final that I realised I had for years not been using the correct figures, I was correct 1.44Ω to earth but it is 0.94Ω line - neutral with an incomer of 0.35Ω but it did depend on the incoming reading. I had been doing as shown in collage and measuring the ring final, but I had made a mistake with the pass figure.
Now this means some one could pull my paperwork some 9 years after submitting it and find I had made an error. Now I had worked for many firms, and did not have copies of the certificates, so I did not know if I had passed something I should not had done or not. Now I have the software on my PDA so I can check in seconds, but before the PDA and phone which could run java script, that calculation was not easy with all the correction factors.
This is now the problem, electricians do have the software and can find faults, which just 5 years ago they were unlikely to find, the whole idea of rule of thumb has gone. I have not done a single EICR without finding something wrong, it may be regarded as satisfactory, but that does not mean there were no faults. Now I like I am sure every other electrician don't want to get caught out, so if I think some one may be checking my work I am more careful, and I will list things I may feel does not really matter. Most councils work on a three strikes and your out. So any electrician doing an EICR for the council will be very careful not to leave himself open to a strike.