SEA BASS FENNEL AND LENTIL TRAYBAKE WITH SALSA VERDE

• 2 small bulbs fennel, trimmed and cut into thick wedges, fronds reserved • 1 unwaxed lemon, thinly sliced • 1 tbsp extra virgin olive oil • 250g pouch ready-to-eat Beluga lentils • 2 large sea bass fillets • 1/2 x 25g pack flat leaf parsley, leaves only • 1/2 x 25g pack mint, leaves only • 1/2 x 25g pack basil, leaves only • 1 large garlic clove • 2 anchovy fillets • 1 tsp nonpareille capers, drained and rinse • ½ lemon, juice • 50ml extra virgin olive oil