Put the barley or spelt in a large saucepan and cover generously with water. Bring to the boil and simmer for 45-60 minutes (longer if using spelt) or until tender.
Add the chopped cabbage and return to the boil for 1 minute until the cabbage has a vibrant colour. Drain immediately, rinsing well under the cold tap. Set aside to drain.
Heat the oil in a large, heavy-based frying pan, add the pine kernels or almonds and toast until fragrant and golden brown. Add the raisins, drained barley or spelt and cabbage. Sauté over a medium heat for 2-3 minutes to warm through.
Add the vinegar and cook for a further 2-3 minutes. Stir in 3 tablespoons of the parsley and add salt and pepper to taste. Set aside in a warm place.
Meanwhile, prepare a steamer by filling the base with water and bringing it to the boil. Lightly season the fish with salt and pepper and place in the steamer to cook for 6-8 minutes, depending on the thickness of the fillets.
Pile the barley or spelt mixture onto warmed serving plates. Top with the steamed fish and sprinkle with the remaining parsley, the lemon juice and some more black pepper. Serve at once with lemon wedges.
Spelt is available in health-food shops and delicatessens.