An old aerial photo from the 1950s was recently found and discovered to show details of a replica World War One battlefield, complete with two sets of trench systems and a "no mans land" between them, near Gosport. It transpired this was a training area where soldiers were able to practise before being sent off to fight on the Western Front.
Amazingly this site has remained untouched for the last 100 years and apart from a being a bit overgrown is pretty much the same as it was all those years ago.
The trenches around the cache location are still very well defined and well worth a bit of investigating, with a bit of imagination you can get a feel of what it might have been like.
You can find a bit more information on this link:
http://www.bbc.co.uk/news/uk-england-hampshire-26471922
You are looking for a small cache, well hidden but within one of the trench systems. I wouldn't recommend wearing your Sunday best !!