Heat the oil in a large pan and fry the shallots and garlic gently for 5–6 minutes, to soften but not brown. Add the stock, saffron and bay leaf and bring to the boil.
Add the potatoes to the pan, reduce the heat, cover and simmer gently for about 10 minutes until tender.
Increase the heat to high and add the frozen mixed vegetables. Bring back to the boil, then stir in the tomatoes, cod and seafood cocktail. Reduce heat and simmer gently, without stirring, for about 3 minutes until the cod is white and firm. Season to taste, then serve immediately.