Bake the chicken chargrills according to the packet directions. If using the chicken breasts, brush with a little oil and grill until cooked.
Meanwhile, cook the pasta in boiling, salted water, for eight minutes.
While the chicken is baking and pasta cooking, prepare the sauce. Heat the sunflower oil in a saute pan and saute the onion until it begins to soften, about five minutes.
Add the garlic and cook for a further minute before adding the tinned tomatoes and tomato puree. Simmer gently for five minutes until the sauce thickens slightly.
Stir in the pesto and cream cheese and cook a further minute or so until the cream cheese melts. Stir in most of the chopped parsley (reserve some for the top), remove from heat and set aside.
Chop the cooked chicken chargrills into bite sized pieces.
Combine the cooked pasta, bite sized chicken pieces, frozen peas, frozen sweetcorn and sauce together and transfer to a casserole dish.
Sprinkle with the three grated cheeses and top with the remaining parsley. Turn the oven up to 200 C.
Bake in the middle of the oven for 15-20 minutes, until the cheese is golden and bubbly.