Iping is the setting for the classic H. G. Wells science fiction story (1897) The Invisible Man. Wells knew the area well having lived nearby in Midhurst in the early 1880's.
This is the bonus cache for The Invisible Man geocaching adventure.
You can find further details about the smartphone app for Adventure Labs here: https://labs.geocaching.com. If you already have the app then search on nearby Adventures to find The Invisible Man.
You will be given the cache co-ordinates when you complete the adventure.