Cox's Meadow, named after the last farming family to own this land in the early 20th Century, has been a public space since the 1950s. In the early 21st Century, it stopped being an actual meadow and became a major part of the Flood Management Scheme - hard to believe that the little River Chelt could do much damage, but in 2007 the local area lost water supply and very nearly power as a result of floods.
These days it's a very popular place for dog walkers, learner cyclists and a useful footpath/ cycle path into town from Charlton Kings. Its slopes are also great for a bit of sledging action on snowy days. And there's a cafe & layby for parking (if the dog walkers haven't taken up all the spaces!)
You are looking for a magnetic nano in a place where you can find out even more. You will need your own writing implement and tweezers. Please take care to replace the container back with the magnetic disc to prevent the cache from going for a walk round the park!