Finely chop half the bacon. Heat oil in a small frying pan over medium heat. Cook chopped bacon, stirring occasionally, for 5 minutes or until just starting to turn golden. Add onion and garlic. Cook, stirring, for 2 minutes or until onion softens. Remove from heat. Set aside to cool.
Combine zucchini, sweet potato and cheese in a large bowl. Add cooled bacon mixture and flour. Mix well. Add milk and egg. Season well with salt and pepper. Mix well to combine.
Add enough extra oil to a large frying pan to reach 5mm up side of pan. Heat over medium heat. Spoon ¼ cup batter into pan, spreading to form a round. Repeat 3 more times to make 4 fritters. Cook for 4 to 5 minutes each side or until golden brown and cooked through. Transfer to a tray lined with paper towel. Cover loosely to keep warm. Repeat with remaining batter, adding extra oil to pan when necessary.
Meanwhile, reheat the small frying pan over medium-high heat. Add remaining bacon to pan. Cook, turning for 5 minutes or until golden and crisp. Drain on paper towel. Serve fritters with bacon, salad and yoghurt.
