Toilets will be size appropriate with toilet paper on rolls. Staff won't routinely help wipe, etc though if there are accidents they will assist, obviously. Send a spare change of pants and trousers in a bag just incase.
Please don't send in flushable wipes. They cause no end of issues with plumbing, etc. They really shouldn't be flushed, regardless of what they are called, and there won't be bins in the toilet cubicles.
Food will be school dependent. However, all infant school pupils in England are entitled to a free lunch at school. There will be a menu to select from, it's often a rolling 3 week menu with a main option and a vegetarian option. Some will also offer a jacket potato and/or sandwich option too. Some schools do this daily - we do, we ask the children each morning, and others ask parents to make the selections in advance, often on an app/online site. Most also allow children to bring in their own packed lunch. Where these are eaten will vary in each school dependent on hall space, etc. We sit packed lunch children in a classroom as we are limited in hall space. Make sure packed lunch boxes are labelled.
Milk will be provided daily for free until the child turns 5. You can chose to pay for it after that.
Fruit/veg snacks are provided daily, free of charge, in infants. Some schools allow children to bring in their own healthy snacks but others won't allow this. It will be school dependent.
You will be expected to send your child in with a water bottle daily. They] children are normally only allowed water in this. Some insist on transparent water bottles, others don't. Make sure it is labelled with your child's name.
Your child will usually need a bag - usually called a book bag. Where possible avoid big backpacks as many schools have limited storage space for bags, coats, etc. Make sure this is labelled too. You may be asked to provide a bag with a change of clothes in too, incase of accidents. Some schools ask children to have indoor shoes, not all. Some ask for children to bring in PE kits for their pegs, but some simply ask children to come to school in kits on the pe days.
Infact make sure everything is labelled clearly - name on bags, objects, coats, uniform, everything!
In September there may be a staggered start so try to find the details of those in advance. Some schools start everyone full time on day 1, some stagger it over a week or two.
I would contact school early next week to get an information pack. They will have usually been sent out after the initial admissions dates came out so obviously as yours is a later entry I'd phone to chase - simply as many schools finish on Friday, or the week after. You may be able to get a short transition session sorted next week too, even if it's just a walk round tour.