Preheat the oven to 180c.
Prepare the couscous first. Put the couscous in a large bowl and pour over the hot vegetable stock. All the couscous should be submerged under the stock. Cover with clingfilm and leave for 10 minutes.
Add the cherry tomatoes, peppers, and courgette to a baking tray. Drizzle with the olive oil and season with salt and pepper. Give the pan a good shake so all the ingredients are mixed with the seasoning and oil. Roast in the oven for 20 minutes or until they begin to soften and brown.
In the meantime, add the sundried tomato oil to a bowl, then add the lemon juice, Dijon mustard and season with salt and pepper. Whisk well, until you have a thick, creamy dressing - around 2 minutes. Put to one side.
Back to the couscous. Take off the clingfilm and using a fork, separate the couscous. Then add the roasted vegetables (they can still be warm from the oven), chopped olives, chopped sundried tomatoes, crumbled feta and the dressing.
Give the couscous a good mix, making sure all the ingredients are combined.
Serve the couscous salad with more fresh parsley and a squeeze of lemon juice.