2) Shape mixture into balls about 5cm in diameter. Toss balls in remaining 1/2 cup flour to coat all over. Set aside until oil is hot enough to fry.
3) Heat oil over medium-high heat until about 190C. Test with some extra falafel mix to see if the temperature is right; it should sink and rise to the surface and float. Add falafel balls in batches so as not to crowd them and cook until crisp and golden, about 8 minutes. Carefully remove from oil and drain on paper towels.
Fill pita halves with a few falafel balls, cucumber, lettuce, onions and peppers, and top with yoghurt sauce.
Combine all ingredients in a bowl until well incorporated. Season with salt and pepper, to taste. Refrigerate until ready to serve.