I read that I need to have detailed book keeping in my possession if I go down the self employed route (it would only be a few hours a week with regular income to top up the other normal job) however, the self employed job is tutoring to a adult a language which I know well and they don't. I'm not really sure how I can put much detail at all. They would simply come to my home, I'd tutor them for a hour a day, or more and they would five cash in hand and I'd have to declare it.
How can I give as much info as I can in case it is ever requested?