Trim the hard ends from the beans. Heat a BBQ grill to high and grill the beans for about 5 minutes, turning regularly until they are softened and slightly charred. Cut into 5cm lengths. In a large mortar and pestle pound the garlic and chilli to a coarse paste. Add the golden syrup, fish sauce and lime juice and mix well. Add the cherry tomatoes and bruise with the pestle to extract their juices. Taste and adjust seasoning. Stir the grilled beans through the dressing and toss with the basil leaves.