Well done on passing c and c&e mate! I am only c just now and am new. Most wouldn’t call truck driving good hours, but from 80 hours a week, you will probably see the benefit!
As for what to take with you, IDK, I have in my bag, daily drinks and food, glucose meter and fast carb tablets (because the dvsa are knuts and I have to check blood glucose every 2 hours) trainers for if my feet hurt in my boots and I am doing 2/3 hours driving, window cleaner in a spray bottle (the sun on a dirty screen makes vision near impossible) and a roll of kitchen paper, sun glasses, phone holder to stick to screen and charger, spare phone which has nav software on it (Navmii) my driving diary (I record all work, pay and hours in it, also any issues and stick the tacho print out into it if I feel the need for one) and air freshner! Agency trucks can be the dirtiest places I have found.
I think that is about it. this is just for day driving, I also make sure I have cash with me for emergencies.
ATB,
Tommy.