First cook the potatoes. Place them in a large saucepan of boiling water and boil for 15 minutes or until tender.
Meanwhile, pat the veal dry with paper towel. Season the flour with a little pepper, then toss the veal in the flour to coat it lightly and evenly all over. Shake off any excess flour.
Heat half the oil in a large nonstick frying pan over medium heat. Add half the margarine and heat until it starts to foam, then add the veal. Fry for 2–3 minutes on each side or until the juices run clear. Remove the veal from the pan, place on a warmed serving dish and keep hot.
Drain the potatoes in a colander. Add the remaining oil to the hot saucepan in which you cooked the potatoes and set over low heat. Add the potatoes and toss gently until they are coated with oil. Add the spinach to the pan in 4 batches, gently tossing and stirring so that it wilts in the heat from the potatoes. Add the lemon juice and season with pepper. Stir gently to mix. Cover and keep warm while you make the sauce.
Return the frying pan to the heat and add the white wine. Increase the heat so the liquid bubbles, then stir vigorously to dislodge any bits of sediment in the bottom of the pan. Boil for 1 minute or until reduced and syrupy. Remove the pan from the heat and add the rest of the margarine. Stir until it has melted. Scatter the mixed herbs over the veal, then drizzle with the wine sauce. Sprinkle the lemon rind over the potatoes and spinach. Serve the vegetables alongside the veal, with lemon wedges for squeezing.