For most meat joints, the easiest roasting guide to follow is turn the 200°C (180°C fan) mark 6 and cook the meat for:
Cooking Guide Meat Joints
Beef (medium) – 25min per 450g (1lb)
Lamb (medium) – 25min per 450g (1lb)
Pork – 35min per 450g (1lb)
Chicken – 30min per 450g (1lb)
For beef and lamb, cook for 5min less per 450g (1lb) if you prefer rare meat or add an extra 25min on to the cooking time if your prefer your meat well done.