Are the setters just being sloppy when one clue says “The gully” and another says “A gully”? Maybe they skipped the lesson on definite and indefinite articles in English class. No, in fact, they’re giving you some help in finding that control.

Whenever you see “THE windmill” you are being told that the windmill you are looking for is the one shown on the map. If it says “A windmill”, then this means that there does exist in real life a windmill, but it is not shown on the map. The circle showing where the control is will be in the correct spot, but it just won’t have a windmill at its centre on the map.