I have some experience of wiring and a degree in Electrical Engineer so all the principles and calculations side of it's straightforward, it's more how todo things in accordance with IEE guidelines that I'd need to learn.
The most important question is why do you want to do this? What is your goal?
If you want to become an electrician then in all decency and professional responsibility you should go down the proper C&G route, including if at all possible some time as an apprentice or "helper" to gain practical experience.
If you just want to do it for your own personal satisfaction, or because you've got a big DIY project coming up and you want to sweet-talk your LABC then the
EAL Level 2 Certificate for Domestic Electrical Installers would be appropriate.
How hard is itto become Part P qualified?
Pace the comments above about that term, nowhere near hard enough, IMO.
If there's an intensive course that I can take for a few weeks then some exams, I'd be seriously tempted!
There are loads of commercial training companies who will take your money and push you through the EAL VRQ in 5 days, but you'd get more out of it, and spend less, if you did it as an evening class at your local college.
Given what you say above, you'd probably have no problems in completing the course and getting the qualification, and armed with that, a few examples of your work to show, an investment in some test equipment and a good enough understanding of safe isolation, testing procedures, the theory of what test results mean etc, you could become registered and set yourself loose on an unsuspecting public as a qualified electrician. Without any experience of installation work, without any knowledge of all the practical tricks and techniques, without any manual skills, without any experience of fault-finding, without any product or design knowledge with which to advise your clients, without any knowledge of anything beyond the narrow scope of the EAL course, etc etc etc.
Hence my first question....