Bus stop Co-ordinates North 50 48.022', West 000 02.408'
The cache is NOT at the above co-ordinates and you do not need to visit the above co-ordinates to find it. It is however more or less the nearest bus stop to the Cache, and a short walk from it. .
What is Parallax
Parallax is a technique that is mostly used by Astronomers to find the distance to stars and planets. However the principle can be used to locate an exact spot, say the location of a cache. In the first picture below there is a distant object, the wind turbine, and a near object, the sapling. From position A the sapling looks to the right of the turbine. From position C the sapling looks to the left of the turbine. Only along the line labelled B, will the two be exactly lined up.
Now look at the second picture below. This shows that if you line up distant object A with near object B, and also line up distant object D with near object C, when all 4 objects are lined up you can only be in one spot. It is a surprisingly powerful way of finding an exact location.
Finding the Cache
Take a look at the two photographs of the saltdean saefront below. Both were taken standing exactly where the cache is placed looking different ways. In order to find the cache you need to position yourself so that you can see both these views exactly lined up as you see them in these photographs, and then you are at GZ. Pick something near and far in each photo and line them up exactly as they are in the photos. I've drawn dashed lines down the middle of the pictures to help. Then look down near your feet, you won't be far away.