evidence documents to go with application

[londoner23]

Hi

i have a question regarding the documents required for section 4 of the application. I'm a student currently at University, would I have to request a letter from the university to say I'm enrolled on a course from date x to date y, or would a welcome letter or something similar be sufficient evidence? The same would go for my sixth form, would I have to contact my sixth form and request a letter saying I was a student there from 2006 to 2008 or could I maybe use my a level certificates?

Also I took a gap year before going to University which is part of the 5 year period, I didnt travel, I was in the Uk most of the time but I havent really got any evidence to say I was exersizing treaty rights, I was working on and off but through agencies. Would I simply need evidence of enrollment in education ie. sixth form + university or do I have to explain the gap year as well?

Maybe I should also mention I'm an EEA (Czech Republic) national, been in the UK since I was 11 in 2001.

Any advice would be great, thank you