Cod en papillote with caponata

Name: Cod en papillote with caponata
Ingredients: 4 x 160g portions chunky cod (we used Right Said Fred); 15g fine sea salt; 1 tsp sugar; zest of ½ lemon; 1 aubergine; ½ tbsp fine sea salt; 30g golden sultanas (or regular); 30g toasted pine nuts; 6 tbsp vegetable oil; 1 courgette; 1 red and 1 yellow pepper; 2 celery stalks; 1 red onion; 250g baby plum tomatoes, roughly chopped; 90ml white condiment balsamic vinegar; 60g caster sugar; 50ml extra-virgin olive oil; 100g Nocellara or other pitted green olives; 8 basil leaves, plus extra to garnish