The cache is not at the posted co-ordinates, but the spot is worth a visit if you are visitor to Winchester. In order to find this cache, you will need to complete the Military Winchester Set of Adventure Lab caches.
The Adventure celebrates Winchester's place as a military centre over a number of centuries.
To find the cache, you must visit all five Adventure Lab locations and make a note of the bonus clue at each one. Then substitute the numbers you find into this equation:
N51 03.ABC W001 19.DEE
To complete the Adventure Lab Series, you will need a Smartphone and the Adventure Labs app.
Here's a linky:
Military Winchester Adventure Labs
You can validate your puzzle solution with certitude.