Preheat the oven to 200ºC/180ºC fan/gas mark 6. Cook the sweet potato fries according to the instructions on the packet.
Meanwhile, pat the sea bass fillets with kitchen paper. Spoon the flour on to a large plate and season with black pepper. Pat the sea bass fillets in the flour, coating well.
Meanwhile, heat half the oil in a non-stick frying pan. When hot, cook 2 sea bass fillets, skin side down, for 3 minutes. Turn the fish over and cook for a further 3 minutes until golden and crisp. Remove from the pan and keep warm. Repeat with the remaining oil and fillets.
Cook the spinach, broccoli and asparagus according to the instructions on the packets. Carefully transfer to a large bowl and toss together before serving with the fish and sweet potato fries. Serve with a squeeze of lemon juice and more freshly ground black pepper.