This is a local series started by Bigears74 and is such a good one I have added to it!
There is nothing at the above co ordinates - except a very nice park, with Jill's Garden (a memorial to local girl Jill Dando) and a recently restored bandstand.
Where would you find this stone?
When you find it you are within 20 feet of the cache.
Vg'f oruvaq lbh, ghpxrq oruvaq n gryrtencu cbyr.