Combine all the spices and ½ tbsp salt together in a pestle and mortar. Give everything a good grind, keeping a little of its coarseness. Rub the oil and then the ground spices all over the beef and massage in well. Cover and chill overnight to marinate.
Next day, heat oven to 190C/170C fan/gas 5. Weigh your joint and roast for 10 mins per 450g for rare meat and 15 mins per 450g for medium, plus an extra 20 mins. Cover and rest for 20 mins while you finish the salads, then slice and serve. Alternatively, roast the beef in the morning and serve at room temperature for dinner.