Caz, Charmingly, Lemon, Cristiane, sorry it's taken me a while to get back to you.
Savoury flapjacks - can be plainer for kids or pimped for grown ups. Freeze well and can reheat or warm up in the oven.
200g oats
200g grated cheese
200g grated courgette
200g grated carrot
2 small or 1 medium onion, finely chopped
2 eggs, beaten
salt & pepper
Sweat off the veg til softened, add everything else. Put into a lightly oiled tin and bake at 190 degrees C for 30 mins. Let them cool and firm up a bit before you cut.
Swap carrot for sweet potato or do half and half, add toasted pine nuts, pesto, add garlic to the veg, use a more exciting cheese than cheddar (gryere?). Chopped olives would be nice, sundblushed tomatoes. Adapt as you like I reckon.
PS - I guess these are quite healthy, but overall I don't think that snacks and treats have to be uber 'healthy'. Nothing is inherently unhealthy really, it's more about quantity and frequency eaten. If you stuff yourself with butter and sugar all day everyday, bad news, but a biscuit or two in the middle of a every diet that is a healthy balance of fruit, veg, lean meats, fish, fibre etc, no problemo I reckon!