Spread the peppers, onions and tomatoes out on a baking sheet and drizzle with half the oil. Sprinkle with salt and pepper and roast at 200°C for 20-30 minutes until a little charred and soft.
While the vegetables are roasting make the falafel. Put the chickpeas, harissa, cumin, coriander, sesame seeds, aleppo chilli flakes and garlic into a blender and blend until smooth. Make into 6-8 patties. Heat a griddle over a high heat with the rest of the oil. Cook the patties for 5 minutes on each side then remove and place on a paper towel lined plate.
Serve your falafel with the roasted vegetables, the olives, feta, lemon wedges, coriander, pitta bread and the yoghurt mixed with cucumber chunks.