Hi Tfo welcome to the forum
for your information I'm currently doing the city & guilds level 3 2365 diploma and it is the follow on course from the level 2 2365 diploma. This course is a very intense theory based course and I find that being in a classroom environment certainly helps me and I can honestly say I would not have been as confident now if I could not have cross referenced my calculations with my fellow classmates. I have helped my younger classmates through the practical level 2 diploma as they had little practical experience and they are now returning the favour by helping me on the theory calculations I struggle with as I'm a mature student. My level 3 course is full time 2 days a week and I work on electrical installations the other 3 days a week. Home learning and study at home courses are good for some people but my personal advice is you cant beat a classroom environment where you will have students at the same level as you and who will be able to help you where you are struggling.
Good luck and stick with it you will need the level 3 diploma certification and the NVQ/AM2 to gain a fully qualified electricians gold card.