Bring half a gallon of water to the boil and stir in the salt. Bring off the heat, pour in the other half and the peppercorns and bay leaves. Leave to cool to room temperature and add the whole chicken, then leave in the fridge for roughly 4 hours.
Whisk the buttermilk, coconut milk, garlic and paprika together and pour over the chicken, rolling it around to cover it. Cover and leave in the fridge to marinade for at least 12 hours.
In a large tray whisk together the flour, semolina, cornflour, pepper and salt. Remove the chicken from the marinade and allow most of it to drip off, then roll it in the floury dredge.
Preheat oil to 180°C/360°F in your largest pan - it's going to foam up quite a bit so make sure it's both deep enough for the chicken to be completely covered and to allow room for the oil to rise up. Before adding the chicken turn the heat up underneath - putting in the chicken will cool the oil down so you want to compensate for this sudden drop in temperature.
Hold the chicken firmly with tongs in the cavity and against the backbone (it doesn't matter too much if the crispy skin comes off here) and carefully lower it into the oil. If you have a pasta basket deep enough to immerse the chicken this is even better and safer. Turn the chicken over in the oil and move around in the pan to make sure it doesn't get stuck to the bottom for roughly 12 - 15 minutes. Check with a temperature probe in the thigh - if it's undercooked finish it off in the oven for 10 minutes.