Extreme care must be taken with the map survey and the placement of the circles, the centre of which must represent exactly the placement of one of the cluster of posts.
Take control 6 for example. In view 1, seen from the NE, the
centre is round the leftmost 'A' post.
View 2, from the NNE, gives an apparently different post
setting although the answer is still 'A'.
A third decision position, seen from the N is shown in View 3,
in this case the answer is 'B'.
Refer back to View 1 and the map as viewed from the north. If the circle were now to be centred on the 'C' post a further set of answers would be available.