We got a very detailed packed lunch policy last year. Not that it has been enforced! I’m sure they would say something about crisps, nuts or chocolate (as they’ve been ‘banned’ for ages), but we also got stuff about only having occasional sausage products (like sausage roll, cooked sausage) and needing a source of omega oils etc... they haven’t gone so far as to write home about stuff like that. Both of my DCs are a bit tricky to feed for lunch (both autistic).
Eldest is easier to cater for, he takes a mix of things - usually grapes, strawberries, tomatoes, breadsticks, yoghurt, then the final item will vary; sometimes cooked sausage, sometimes hummus, sometimes pumpkin pie.
It ‘looks’ good, but actually I don’t see how that would be better than a ham sandwich for instance, he just won’t eat a typical packed lunch and doesn’t touch much of what’s on offer for school dinners.
My younger one will have yoghurt, cocktail sausages, crackers/breadsticks, Soreen... it starts to get tricky after that!
If he’d eat a sandwich and crisps etc reliably then tbh I’d probably be sending him in with them, given there’s little he’ll reliably eat at school, although he doesn’t complain of hunger and he’s not underweight so he clearly makes up for it before and after school!
Both take water bottles, getting them into that habit was more important to me because for ages they refused water but I didn’t want them to live on squash - I don’t actually think it’s awful, but I don’t want them needing everything to be sweet and they’re both fine drinking just water now. However when they were very little and not drinking, especially in hot weather, I just gave them the squash! Things can be a work in progress, I don’t think children need to be perfect and unfussy at 4yo and it’s more about regularly offering and modelling the variety of food and them seeing things like fruit and veg as part of a normal diet and not overly relying on things like chocolate biscuits for sustenance.