Heat the olive oil in a frypan over medium heat and cook the onion until tender. Mix in garlic and cook until heated through. Mix in beans, tomatoes and capsicum. Season with basil, oregano, salt and pepper. Continue cooking 10 minutes, stirring occasionally.
Melt the butter in a saucepan over medium heat and gradually mix in flour until smooth. Slowly stir in the milk. Mix in Parmesan cheese and continue to cook and stir until slightly thickened.
Spread 1/2 the red bean mixture in casserole dish and top with lasagne. Layer with remaining bean mixture and remaining lasagne. Cover with the cheese sauce and top with Gruyere cheese.
Bake 20 minutes in the preheated oven or until lightly browned.