There is a division among cooks about whether to parboil. I prefer to boil peeled potatoes in salted water for about 5 minutes and then shake them roughly in a colander to break up the surface. Some people scour the potatoes with a fork. You can dust with a little flour if you like. Some people recommend a light coating of semolina, but I have not found that it makes much difference. Sprinkle with sea salt.
Never cook the potatoes round a joint of meat as this can make them soggy (and pan juices should be kept for the gravy). The fat must be hot when you put in the potatoes and they need to be roasted for a minimum of an hour in a hot oven –
Roast potatoes are lovely on their own. They don’t necessarily have to share the plate with meat.