Preheat the oven to 180ºC, fan 160ºC, gas 4. Mix the garlic with the butter. Finely chop a quarter of the basil leaves and mix into the butter. Spread on the ciabatta and wrap in foil parcels. Set aside.
Put the tomatoes in a roasting tin and drizzle over the olive oil, Worcestershire sauce, balsamic vinegar and Tabasco. Scatter over the sugar and half of the remaining basil leaves. Put the garlic bread on the top shelf of the oven and the tomatoes below, and cook for 15-20 minutes. Unwrap the bread for the final 2 minutes of cooking time to brown the edges.
Pile the roasted tomatoes on top of each ciabatta and spoon over any juices in the tin. Garnish with the remaining basil leaves and freshly ground black pepper.