Preheat the oven to 180C/160C Fan/Gas 4. Line the base and sides of a baking tray with aluminium foil.
In a bowl, mix together the paprika, black pepper and salt until well combined.
Put the chicken legs on a chopping board and carefully score the skin of each leg 5-6 times using a sharp knife.
Roll the scored skin of each chicken leg in the salt and paprika mixture, pressing down to coat evenly. Place the spiced chicken legs on the prepared baking tray.
Wash and pat dry the potatoes and prick each 3-4 times with a fork to stop the skins splitting when they are baked. Add the potatoes to the baking tray. Bake the chicken and potatoes in the oven for 1 hour.
Meanwhile, for the barbecue sauce, in a bowl, mix together all of the barbecue sauce ingredients until well combined.
Remove the chicken from the oven and increase the oven temperature to 220C/200C Fan/Gas 7.
Brush the chicken legs all over with the barbecue sauce, then return the chicken and potatoes to the oven and continue to cook for a further 12-15 minutes, or until the potatoes are tender and the chicken is cooked through with sticky, dark-brown skin. (The chicken is cooked through if the juices run clear when the meat is pierced with a skewer in the thickest part, and no trace of pink remains.)
Meanwhile, for the sweetcorn, half-fill a saucepan with water and bring it to the boil. Add the frozen corn-on-the-cobs and return the water to the boil, then cook the sweetcorn according to the packet instructions, until tender. Drain well, then return to the saucepan and stir in the butter until melted. Season well with salt and freshly ground black pepper. (Alternatively, cook in the microwave according to the packet instructions, then add the butter and seasoning.)
Just before serving, shred the chicken meat using two forks to pull the meat apart. Discard the bones, but keep the skin (thinly slice it with a sharp knife if you cannot shred it).
Serve the pulled barbecue chicken with the buttered corn-on-the-cobs and the baked potatoes alongside. Sprinkle over the parsley or chives. Serve the soured cream and chive dip (or crème fraîche) in dipping bowls alongside, if using.