Heat a barbecue to medium.
1) Cut the peppers and aubergine lengthwise into quarters and put into a large mixing bowl.
2) Add the garlic and coriander seeds, to a mortar and pestle, and crush them into a chunky paste.
3) Transfer the paste to the mixing bowl with the vegetables. Add the remaining ingredients and toss to coat well. Put on the hot grill and cook for about 5 to 7 minutes on each side.