You can do all of it yourself.
If in England, none of it is notifiable.
If in Wales, it might be notifiable due to being in a kitchen.
Whether notifiable or not, you can still do the work yourself.
If not England or Wales, there is no Part P.
No such thing either.
The situation is that in England and Wales, anyone can do any electrical work in their home, provided it complies with Part P - the single paragraph linked to previously about protecting persons from fire or injury.
For a few specific types of work, you must notify building control first. Wales has more notifiable things than England. Almost all electrical work is not notifiable. Notification involves paying a fee, usually £100+
An alternative to you doing the work and paying a fee £100+ is to employ someone who is a member of a self-certification scheme. They will do the work and notification as well. Because they pay an annual membership fee of £100s, they can notify individual work for a few pounds rather than £100s each. Probably a cheaper option for smaller work.