There seem to be at least two local geocaches in the park. Here are the links, but free registration there is required to see the terms and conditions logs and exact locations. https://www.geocaching.com/geocache/GCA49VD
N 50° 50.583 W 000° 46.700
British Grid: SU 86109 05553 https://www.geocaching.com/geocache/GCA4VGF
N 50° 50.696 W 000° 46.604
British Grid: SU 86219 05765