Before the urban sprawl of Worthing engulfed this area between the wars and early 1950's, this spot was occupied by Filstone Nursery. Much of the area was given over to agriculture, and just along the road was the water well, used by many as their primary source of water only a few decades previously.
The last recorded local entry for the nursery before its sale and subsequent building on the area dates to 1947, when Kezia Ann Warren died on the 14 November, leaving the Nursery as her place of death.
Nothing now remains of what once stood here, although some of the stone walls along the south side of thr road do look built to an old design, and the road hasn't deviated from its original path prior to the house building. Further along there is an old cottage converted from what was once a coach house (citation needed). Perhaps the builder's in their rush to destroy all that was old overlooked this small reminder of what was once quite a quiet backwater
The cache itself should be a pretty easy find, with only the passing muggles on foot and car to interrupt your searching. Should anyone know more about this area and its history, please do contact me, as I would be interested in finding out more.