Roast whole fish with salsa romesco

Name: Roast whole fish with salsa romesco
Prep time: 20 min
Cook time: 20 min
Total time: 40 min
Cuisine: Mediterranean
Ingredients: 2 whole farmed sea bream sea bass or other sustainably caught medium-size white fish, about 500g each, scaled and gutted (ask your fishmonger to do this for you); 2 lemons thickly sliced; buttered or sautéed new potatoes to serve; 3 red peppers deseeded and cut into quarters; 600g ripe red tomato roughly chopped; 1 garlic clove crushed; 1 red chilli deseeded and finely chopped; handful flat-leaf parsley stalks and leaves separated; 50g blanched hazelnuts roughly crushed; 1 tbsp sherry vinegar; 3 tbsp extra-virgin olive oil plus extra for drizzling