Don't know any electricians who worry about Part L TBH . I think thats the architect's or designer's problem.
If its all domestic ag95 you just need to register for submitting stuff to Local Building Control . Stroma is half the cost of the others but insurance companies only recognise NICEIC . They don't know that the schemes were expanded .
We had the NI thing at the farm, I'm the maintenance manager on a part time basis, when we expanded the grain store side we were offered some "free friendly help" by our insurers. they'd send one of their bods over to spend a day looking round to "make sure you comply with all relevant regs, HSE etc" . What it was, was actually an excuse for them to snoop, anyway she went all over the site and then we retired to the office, that's when the fun started.
She wanted to see all the paperwork, coshh sheets ,RAMS etc regarding the handling of the chemicals, then she moved on to fire plans, incident management and so on.
Eventually she enquired as to why we had no paperwork for the electrics, "they're all in that file in front of you" I replied, "the one marked electrical certificates". we keep a folder with all the test sheets, inspection dates, and PAT logs in!
She looked at the paperwork, "oh these are no good, they need to be done by an NIC registered electrician" she said, I glared at her, "Hang on a minute, there's nothing in law say's you have to do that, now unless you want to start talking about restrictive trade practices, which is a different matter" I snarled.
She closed the file, "I'll ask when I get back to the office", a couple of weeks later she returned with some stuff she'd promised to bring, we had another meeting and the subject of the electrics wasn't mentioned so I brought it up. "oh that, yes it's fine" she replied, "as long as the paperwork is up to date, and the person doing the work is competent then we're happy".
So much for a "bit of help to make sure you comply with relevant regulations", I knew it was a snooping exercise, funny how she changed her attitude when she realised I wasn't falling for her BS!