What a handyman may do
A competent handyman can carry out simple, non-notifiable electrical tasks: replacing a like-for-like light fitting, swapping a faceplate, or changing a plug. These are low-risk and do not require certification.
What needs a registered electrician
Notifiable work under Part P of the Building Regulations must be done by a registered electrician (NICEIC or NAPIT) who can self-certify it: new circuits, consumer-unit (fuse-board) changes, and most electrical work in bathrooms and kitchens.
Skipping this is a false economy — uncertified work can fail a sale, invalidate insurance, and is genuinely dangerous. The electrician’s rate includes the test certificate you are required to keep.