Using a vegetable peeler, thinly slice the courgettes, then rub over the oil and season well. Heat a griddle pan until smoking, then add the courgettes and cook for about 2 minutes. Turn over and cook for a further 2 minutes until just soft and lightly charred. Set aside.
Cook the pasta in a large saucepan of salted boiling water according to the pack instructions until al dente. Add the peas 2 minutes before the end of the cooking time and cook until tender. Drain, reserving a little of the cooking water, and return to the pan.
Mash half the feta with 2 tablespoons of the cooking water and stir through the pasta, adding more cooking water to loosen if needed. Toss together with the tomatoes and courgettes. Crumble over the remaining feta and serve sprinkled with basil leaves.