Put the dried beans into a pan and cover with plenty of water. Bring to the boil, then cover, remove from the heat and leave to soak for 2 hours.
Cut the bacon into 5mm/¼in dice, put into a pan and cook over a low heat until the fat begins to melt. Increase the heat a little and allow it to fry in its own fat until crisp and golden. Add the onion (and the sunflower oil if it looks dry) and cook for about 5 minutes, until soft.
Drain the beans and add them to the pan with the stock. Simmer gently until they are just tender and the stock is well reduced.
Stand the sweetcorn up on a chopping board and slice away all the kernels. Add the sweetcorn to the beans with the cream and simmer for 5 minutes.
Meanwhile, preheat the grill to high. Brush the pieces of haddock on both sides with the melted butter and season with salt and pepper. Place skin-side up on a lightly oiled baking sheet or the rack of the grill pan and grill for 7-8 minutes.
Stir the chives into the beans and season with salt and pepper. Spoon the mixture into four warmed soup plates and place the haddock on top. Scatter over a few more chives and serve.