My LBC expects homeowners to use installers who are registered;
Part P of the Building Regulations requires that all notifiable domestic electrical installations are fitted safely.You are strongly advised to use contractors registered under a Part P Scheme.
• If these works are carried out by an Approved Installer under the Government’s Competent Persons Scheme, an application under the Regulations is not required.
•
Where an approved installer is not used for the electrical installation (which may form part of other works to the property eg an extension) then evidence that safety standards have been achieved will be required before a Completion Certificate can be issued. This will also apply to DIY installations. The Local Authority will arrange for inspection and testing of the installation and a charge of £400 +VAT will be made to cover the costs.
I know that it doesn't necessarily follow, that being registered makes you competent.
Any-hows, I've emailed my LBC to see who is responsible to notify until clause 3) of previously mentioned Part P.