Cut the squash in half and scoop out and discard the seeds, then crossways into 1 cm (½ inch) thick slices. Place in a large bowl with half the oil and some salt and pepper and stir well to coat the squash. Cook on a medium barbecue for about 10 minutes on each side until charred and tender. Return to the bowl and add the remaining oil, balsamic vinegar, chilli sauce and honey and stir well.
Meanwhile, make the salad. Place the couscous in a bowl and pour over the stock. Leave to soak for 10 minutes, then fluff up the grains with a fork. Stir in the remaining ingredients and season to taste. Serve the couscous salad with the squash.