Tuna and avocado melt

Name: Tuna and avocado melt
Prep time: 15 min
Cook time: 3 min
Total time: 18 min
Cuisine: American
Ingredients: 4 English muffins; 2 Avocados; 1x 420g Tuna; ½ Red onion (diced); ¼ bunch Parsley (chopped); 2 tbsp Sweet chilli sauce; 2 tbsp Mayonnaise; Salt and pepper to taste; 8 slices Swiss cheese