Place prawns, garlic and half the oil in a medium bowl; season with salt and pepper, then toss to coat prawns. Thread prawns lengthways onto 16 wooden skewers.
Cut each slice bacon in half lengthways. Wrap one piece bacon around each prawn, leaving the tails exposed. Preheat a chargrill or barbecue over medium-high heat. Cook skewers, turning, for 4-5 minutes or until prawns change colour and are just cooked through.
Meanwhile, whisk lemon juice, lemon rind, basil, dill and remaining oil in a small bowl until combined. Season with salt and pepper.
Arrange prawns on a serving platter. Drizzle herb dressing over the skewers and serve.