In a large frying pan, poach the haddock in the stock and wine for five minutes. Put on a tray, cover in foil and keep warm.
Bring the cooking liquid up to the boil and reduce by half. Add the prawns, corn, cream and seasoning.
For the mash, heat the butter in a pan and fry off the onions for two to three minutes. Add the mashed potato, cream and nutmeg and beat together.
To serve, put a pile of mash on the plate, sit the haddock on top, add the clams, pour over the sauce, sprinkle with chives.