Where do you want to be ?
Do you want to work for someone else, or are you more interested in doing something that is stand alone (and would you have the skill set for the grind of routing cables under floors, in voids, breaking in back boxes, siting kit etc).
Base format is a few years at college doing the 2330 parts 1-3 for fullest qualification.
Some, such as mates with a few years experience or alternative trades such as alarm, telecom, cabling and engineering simply do the Part P course via an approved scheme provider and enter (tentatively) in to the world of domestic installations. These vary from a minor change to a full rewire of a footballers house, so again the practical skill set is as important as the paper qualification.
To get a JIB ticket, do full fat 2330 then BS2381 / 2391 which will get you a golden wonder season ticket to the wide world of commercial contracting work- about 4 years training and a need to hook up with a firm as a mate / junior. Part P is still required for domestic, as in you must register and be assessed on your work by a scheme provider.
I have done Part P (5 day course / £700) and then followed on with the BS7671 / 2381 (3 day course £500).
I'm ex BT and spent 20 years hands on in offices, factories, schools, listed buildings. residential houses, flats, mansions so my skill set for bashing and cabling had parity with the requirements of 75% of my electricians work.
Without that skill I would have struggled to quote successfully and be able to do the work to the quality and demands required.
The OSG (on site guide) is a good reference book, but I'd go to ebay and see if you can find some Part P course material, and BS2381 material and have a read up of that.
If you go back a few weeks of posts I am sure someone put up a link to the BS2381 dummy exams. Might be worth having a look and a play with those.