Thats a good amount for a 2.5 yr old and a child that age will burn off the sugar, it's about the same as mine would eat at that age (some kids eat more than others, mine eat more than average). I don't worry too much about the contents of the lunchboxes as the kids have a healthy breakfast and evening meal so the usual lunch here is
Ham or tuna on wholemeal (full sandwich for 9 & 6yr olds and half for 4yr old) Or pasta salads with cheese/chicken/ham, pittas/wraps etc. Sometimes I give them a medium sized sausage roll if we are in a hurry (I make the lunches in the morning)
Full sugar Caprisun drink (we don't give sweetners as ds reacts to it so all juice in the house are either fresh juice or full sugar)
Yogurt/fromage frais (full fat)
Crisps/mini cheddars/dairylea dunker/some other savory snack
Cereal bar/flapjack type thing (a proper one with oats and fruit, not the kind thats ricekrispies and choc which arn't filling)
2 pieces of fruit
They use something from thier lunch for thier afternoon break snack, the school provides a piece of fruit/veg and milk for morning break and they have water bottles during lessons. The nursery and reception classes have a help yourself milk/fruit/veg table so the little ones can graze through the day on whatever they want. The most common item to be left in thier lunch bag is crisps which I'll let them eat on the way home as we don't eat dinner until about 6-6.30pm.
I don't limit the fat/sugar or anything at all with the kids meals, active kids will burn everything off, as long as over the whole week thier diet is balanced most of the time they'll be fine. Mine usually have a wholegrain cereal breakfast (porridge with golden syrup/raisins in the colder months) and a piece of fruit and most of our evening meals have some kind of meat in it with loads of veg and some rice/pasta/potatoes so they get everything they need. 1 packet of crisps a day and a treat now and then is good to teach them about balanced eating, I don't add salt to anything I cook so the salt in the crisps is probably the only salt they get most days.
Drives me nuts when the school go on about good food/bad food, I always tell the kids there is no such thing as bad foods, as long as everything is in moderation then it's fine and mine are healthy, happy, slim, active kids.