I agree with Icemum about not buying specific equipment or extra toys until you know how old your first mindee would be, but obviously try to be aware of what you might need (age-appropriate car seats? reins/wrist straps?) to demonstrate to the inspector that you've thought about it.
Do you have to have policies actually completed for this inspection?
You need to be aware of having written permission from parents for lots of things - going out, taking mindees in car, seeking emergency medical treatment etc. I don't think you would have to have this all written up properly, but write lists!!
You will need business rate insurance for your car if you use it - you can tell inspector you know this.
I don't think you'd have to have a proper menu plan done (that can be another item on your list!) but you can tell inspector how important providing healthy, nutritious meals/snacks is.
I think it's so scary for newly-registering minders - there is so much that it seems that you have to do, but the main part is just being aware that (ideally) you have to work towards some of these goals.
I work as a mentor for newly-registering minders, and the best piece of advice I would give is to try and relax! The inspector isn't looking to trip you up!! Good luck.