Thing is, when it's getting late at night, it sometimes difficult to remember which form to use. Suppose it saves on paperwork
OP, just curious about your new consumer unit, could you post a picture with the lid lifted up (one on a hinge)?
To verify if your electrician is in a scheme, you can try this link (think you said he was in NICEIC?);
Competent Persons Register | Home - http://www.competentperson.co.uk/
He should notify your local building control as well for the CU change, if he's in a scheme. If he's not in a scheme, its going to complicate things a bit. It is the home owners responsibility ultimately.