Ah beef roasts. When they are done well they are hard to beat, when done badly they are a formidable weapon for beating. Strangely they are incredibly easy to cook. The difficulty comes in timing the rest of the meal around them. I Like to rub them with a oil based dry rub to form a crust. This depends on my mood and who is around for supper. I like chili flake, crushed coriander seeds, mustard paste, fresh thyme or rosemary - anything really. Just be careful not to put anything that will bitter when pushed a bit far, like fresh garlic. Rather stab the meat and push a clove or two into the roast. That way it won't burn. Or just roast the garlic whole and spread it on after. First prize is roast garlic paste for spreading after.
I preheat the oven till really hot and place the now room temperature meat in the oven and let it roast for a few minutes to form the crust. I seldom roast anything with a lid on it and normally just place it on an oven tray. I then turn it right down and wait until the internal temperature is about 50-54 degrees. Pull it out and rest it properly. Slice and serve.
Horseradish grows like a weed once established. It is very much worth the effort of digging it up and grating it on a sunday.