Season the haddock with salt and pepper. Put 2 tablesp. of olive oil in frying pan and heat gently. Add the fish to the pan, skin side down. Fry until the skin is golden and crisp and the fish is cooked two-thirds of the way through. Turn the fish over and cook the flesh side for another 1-2 minutes until just flaking. Transfer to a plate lined with kitchen paper to drain; keep warm.
Add the remaining tablesp. olive oil to the pan and sauté the tomatoes and scallions for a minute. Add the sugar and a splash of the wine vinegar. Cook over a high heat for a minute or two until the tomatoes are a little soft but still retain their shape. Season the tomatoes and add in the herbs. Divide between 4 warm plates. Put the haddock fillets on top, skin side up and serve immediately with steamed potatoes or some nice bread to mop up the juices!