Dd (9) does not eat her lunch in school very well a lot of the time, claims she does not have enough time, in reality is too busy playing / chatting so I give her a good snack after school at 3pm and then dinner as usual 6.30/7pm. Works well for us. Depending on what she has actually eaten in school I make her one of the following:
Hot chocolate with full fat milk, toasted brown soda bread, real butte and a mini banana
Homemade pancakes (mix keeps for 2 days in the fridge) with a scrape of nutella or crispy bacon and maple syrup
Homemade banana smoothie (banana, yoghurt, honey and full fat milk whizzed in the blender) toasted brown soda bread
Hot choc / or milk with a fruit scone with butter
Brown bread toast with slices of cheese on the side (she especially likes parmesan thinly sliced)
cream crackers with butter and jam
grilled bacon in a sandwich (usually white bread for this but working on it)
petit pain bread rolls hot from the oven with a banana (she loves these)
beans on toast
If she has eaten ok in school she might have something lighter and she loves popcorn / pistachios / fruit / cake / apple tart / biscuit
I try to keep it as healthy as I can get her to accept. She was an exceptionally fussy, hard to feed child and very very slight so I don't worry too much about restricting fat / sugar as she needs it still.