Perfect Roast Pork & Crackling

Dad is the master of roasts.  I bought him The River Cottage Meat Book which is his bible for cooking roasts.  Essentially Hugh Fearnley-Whittingstall swears by starting with what he calls the 'Half Hour Sizzle' at a high temperature, and now, so does Dad.

Dad's scribbled notes I salvaged from the recycling bin read;
20mins @ 220C [Editors note: 20 mins up to 2 kg in weight, 30 mins 2-3kg, & 45 mins over 3 kg]
100mins @ 160C [25 mins per 500g deboned joint, 30 mins bone in joints + belly & loin roasts)
10mins rest

Dad's final flourish was perfect crackling.  His trick to this, he says, is leave the joint uncovered in the fridge overnight, rub in a trickle of olive oil just enough to hold 1 tbsp of course salt onto the rind. just before roasting.  Dad then covers his roasts in a domed roasting dish for the whole cooking time to keep the joint moist and then takes off the crackling at the end of the cooking time and places it on top of the roasting veggies with the oven turned up to 200C for 10 minutes or so whilst the roast rests and then is carved.