Heat the olive oil in a large frying pan.
Add the chopped onion and soften for 5 mins.
Add the smoked paprika, thyme and paella rice in to the frying pan, stir for 1 min, then add the sherry or wine and bring to the boil.
Once the alcohol has evaporated, stir in the chopped tomatoes and chicken stock.
Season and cook, uncovered, for about 15 mins, stirring now and again until the rice is almost tender and still surrounded with some liquid.
Stir in the seafood mix and cover with a lid.
Simmer for 5 mins, or until the seafood is cooked through and the rice is tender.
Squeeze over the lemon juice, add the parsley and serve with the lemon wedges.