Preheat the oven to 190C. Arrange the halved tomatoes cut side up in a roasting tin, drizzle 2 tablspoons of the oil over them and sprinkle with the garlic and salt and pepper. Roast in the oven for 20 mins turning once.
Cook the pasta until al dente.
Put remaining oil in a large bowl with the vinegar, sundried tomatoes, sugar and a little salt and pepper. Stir well. Drain the pasta, add it to the bowl of dressing and toss to mix. Add the roasted tomatoes and mix gently. Before serving, add the chopped rocket, toss lightly and taste for seasoning. Serve at room temperature.