It was my mothers wet room, the builder had run off in to hills of Corwen, and I was left to complete the job, thinking until that point the builder had done everything correct, I contacted the LABC to say I was taking over the job. Seems the LABC were unaware until I told them, but for the building work they had no problem in my son and I DIY, but Part P was new then, and they wanted to employ an electrician at my expense to inspect all the work.
Both my son and I had out C&G 2382 and 2391 but the LABC inspector still wanted a third party inspector, my son said what if he does fail it, what then, if we say it's OK and he says it's not then he will need to be higher qualified to ourselves for you to be able to take what he says as correct, and my dad has a degree. It was only at this point he backed off and decided we could DIY all the electrical work and submit the installation certificate and he would decide on the strength of the installation certificate if he was going to pass it.
As a foot note, when the house was sold, I at first could not find the paperwork, so applied to the LABC for replacements, and was told it would take four months, and I would need to pay the time the council worker took finding them. In other words go away it is only a tax we don't really keep traceable records. Lucky I then found them all, otherwise I would have needed to take out insurance it seems to sell the house.
It seems bathrooms are a special location, and you need planning permission to make a room into a bathroom, or make a bathroom into an ordinary room again. And there are all silly rules about disabled access etc. Distance of pan to the wall, etc, and we had to move the door to get this access, or the builders had, and we found as a result the lintel was only supported on one side, the LABC inspector missed that completely. But insisted an extractor fan even when it has opening windows as he said visitors to the house could look in to the open window. So one was fitted, but never used.
But the LABC inspector is like God, some are easy to get one with, some have a bee in their bonnet, and all you can do it what they tell you. One can read all the documents in the planning portal, but it is the guy would is assigned the case who decides. It is not a simple get an EICR which is clean and your OK, unless the EICR is covered by a scheme provider the LABC inspector does not need to accept it. Although most domestic electricians are scheme members, often the scheme does not cover the issuing of an EICR, even when the document has the providers name on it, read the small print and it often says it's not covered by the scheme. Why electrical factors sell the form pads when down loadable from IET for free, seems to point to electricians trying to con the client that it is covered by the scheme membership.
In the main it is insurance, need professional indemnity insurance to issue an EICR, where I volunteer I don't sharpen my own drills, I have the skill, but not the official training, as it costs the firm money to officially train me, it's not down to ability, but paperwork.