Heat your oven to 200°C/Fan 180°C/Gas 6. Peel the onion and dice it. Peel and slice the shallots. Trim and slice the celery.
Warm 1 tbsp olive oil in a pan. Add the onion, shallots and celery. Season with salt and pepper. Cook over a low heat for 5 mins till soft and golden. Stir now and then. Dice the courgette. Stir it into the onion with the pearl barley. Let everything sweat for a few mins.
Crumble the vegetable stock cube in a measuring jug. Add 450ml boiling water and stir to dissolve it.
Add the stock to the pan. Cover and simmer, stirring occasionally, for around 25 mins till the stock is absorbed.
When the risotto has cooked for 10 mins, place the cod on a square of foil in a baking dish. Season with salt and pepper. Drizzle with ½ tbsp olive oil. Bake for 15 mins till just cooked. It will be white and flake easily when pressed with a fork.
Meanwhile, put the salad leaves in a bowl. Add ½ tbsp olive oil and some salt and pepper. Toss to mix. Finely chop the parsley leaves and stalks. Stir most of them into the risotto. Season to taste.
Divide the risotto between 2 warm bowls. Top with the baked cod, its juices and the rest of the parsley. Serve with the salad and lemon wedges for squeezing.