The question is why do you want the paperwork? You will one hopes inspect and test your work, so there is no danger, so why do you want the legal documents to say some one else has done the work?
When I came to sell my mothers house I could not find the paperwork, I knew all done above board, so asked council for replacements, told it would take 4 months, and would cost however long it took the council worker to find them. In other words go away the Part P registration of work is simply a tax.
This house I viewed the certificates, and thought Oh good, but the readings seemed a little low for such a large house, then found they only covered less than a third of the house.
So we have two documents, the installation certificate, which you do, and either a compliance certificate if done by a third party, or a completion certificate if done by the LABC. All they do is say we are satisfied that the person doing the work is likely to have done a good job.
The installation certificate you can down load blanks for free from the IET web site, so there is nothing stopping you filling them in. You sign to say you have designed the installation, and you have installed it, and also you have inspected and tested it. Some forms all grouped together with one signature, and some have three spaces to sign.
To me the form acts as a check list, you are less likely to miss testing any item when you are filling in the form, there are some items the form does seem to miss, volt drop needs you to either measure how much cable used, or measure the resistance, or measure the loop impedance, you know the limits 3% lights and 5% for rest, and you can calculate what that translates to, for example the ring final is considered to have a maximum of 106 meters.
If you can't work it out, you should not be doing the job, but the formula is in BS 7671 so not much of a problem. You need test instruments, there is no way you can measure 40 mS with a stop watch, so you need the RCD tester, that is likely the most expensive meter, you don't NEED a loop impedance meter, you can use a low ohm meter, with a minimum of 200 mA test current, and the insulation tester can be bought for £35 as can a clamp on meter to measure back ground leakage, voltage etc. I have not found a cheap low ohm meter, but I have one, so have not looked.
You can hire the test kit, although not cheap, as it has to be recalibrated after every hire, which bumps up the hire cost, I have hired when my own kit went for calibration, but for DIY you can measure some know resistor etc, which is likely good enough.
To get the completion certificate in Wales costs £100 plus vat for first £2000 worth of work, England each county can set fees, and you need to inform them before you start, I thought the builder installing my mothers wet room was doing things above board, so when he walked off, I told the LABC I was taking over the job, only to find the builder had not told the LABC, who pointed out in no uncertain terms it is the duty of the owner to ensure it's done.
Next hurdle was to convince the LABC my son and I had the skill, son had done it before with Liverpool and Chester councils with no problem, but Flintshire wanted to use a third party to test and inspect at my expense. It took some persuading, in the end my son said any inspector must of course be higher qualified than us, and my dad has a degree, at which point he did back down and allow us to test, but you can't untell the LABC, once involved that's it, had we know the builder had not informed them, likely we would have also kept quiet.
When I did find the documentation for my mothers house, I realised how daft it was, three installation certificates, and two compliance certificates and a completion certificate with very little to say which linked to what. Dates showed which had been done last, but it did not say if previous work had been re-done. During the re-wire the wet room and kitchen were not done, as it had already been done, but hard to work that out from paperwork.
If you make out the installation certificate, and simply say sorry don't know what happened to the completion certificate, it is unlikely anyone will try and get it from the LABC unless you kill some one. And if you do kill some one, the certificates will be the last of your worries.
If you don't have the skill or equipment to make out the installation certificate, then you should not be doing the work.
