Smoky paprika seafood rice

Name: Smoky paprika seafood rice
Ingredients: 1.3l fish or chicken stock; large pinch of saffron (optional, see tip); 4 tbsp olive oil; 4 garlic cloves, 1 left whole, 3 finely chopped; 12 large prawns, shells on; 4 baby squid (about 250g), cleaned and sliced; 1 onion, very finely chopped; 2 celery sticks, very finely chopped; 1 tsp fennel seeds, lightly crushed; 2 tbsp tomato purée; 1 tsp smoked paprika (hot or sweet); 300g paella rice; 250ml fino sherry or dry white wine; 300g fresh mussels, cleaned (discard any that are open); large handful parsley, roughly chopped; 1 lemon, cut into wedges, to serve