Courgette and pepper ratatouille with fish

Ingredients

• 1 large courgette, cut into 1cm thick circles
• 2 teaspoons olive oil
• 1 medium red onion, thinly sliced
• 2 cloves garlic, finely diced
• 1 yellow pepper, cut into strips
• ½ teaspoon dried oregano
• 1 x 400g can plum tomatoes, drained (keep the juice) and quartered
• Freshly ground black pepper
• Handful basil, roughly chopped
• 4 X 150g skinless white fish fillets
• 500g new potatoes
• 320g fine green beans, trimmed