What I do know about roast lamb is drop the recommended temperature by 25 percent and cook it
for longer, otherwise it'll be tough.

Red meats, such as lamb and beef, can be eaten 'bloody'. It means a shorter cooking time and often results in meat that is not as tender as it would be if you cooked it for hours.

Lamb and goat are at their most tender when cooked for a long time. The temperature setting on my oven lives permanently at 180 degrees C. When I cook lamb, I turn it down to 150.

Another good tip is to take the lamb juices and throw in some ice. The fat will solidify quickly and stick to the ice cubes. You can then use the remaining liquid to flavour your gravy without worrying about consuming the notorious amount of fat that lamb produces during cooking.