Cod olive tagine with brown rice

Name: Cod & olive tagine with brown rice
Ingredients: 3 tbsp rapeseed oil; 2 red onions (about 320g), chopped; 250g swede, finely chopped; 2 carrots (about 200g), finely chopped; 3 strips of lemon peel, finely chopped; 4 garlic cloves, thinly sliced; 1 tsp ground cinnamon; 1 tsp cumin seeds; 2 tsp ground coriander; 400g can chopped tomatoes; 2 tbsp tomato purée; 300ml vegetable stock, made with 1½ tsp bouillon powder; 12 pitted green olives, halved lengthways; 250g easy-cook brown rice; 4 frozen skinless cod fillets (about 360g); ⅓ pack of coriander, chopped