Thinly slice the onion and garlic. Heat the oil in a big saucepan and gently sauté a the onion and garlic.
Add the dried herbs and spices and stir for one minute. Add the tomato purée, stir for a few seconds, then pour in the tinned tomatoes. Rinse the tin with water and pour this into the pan. Season with salt and pepper.
Bring to the boil, then cook for 10 minutes over medium heat to reduce the sauce slightly.
Add the drained beans and corn, cook for another 5 minutes, then add the mixed seafood.
Put the lid on, bring to the boil and cook for 2-5 minutes. (If the seafood was precooked, just bring to the boil and turn off the heat).
Mix in the chopped fresh herbs, season to taste and serve.