Fish pie with pea & dill mash

Name: Fish pie with pea & dill mash
Prep time: 10 min
Cook time: 55 min
Total time: 1 h 5 min
Cuisine: European, British
Ingredients: 375g potatoes cut into chunks; 175g leeks thickly sliced; 160g frozen peas; 2 tbsp half-fat crème fraîche; ½ lemon zested and juiced; 2 tbsp chopped fresh dill; ½ tsp vegetable bouillon powder; 100g cherry tomatoes halved; 250g skinless cod loin cut into large chunks; 50g Atlantic prawns (thawed if frozen); veg to serve (optional)