The above co-ordinates are for the Tower on Leith Hill, the
highest spot in Surrey. Nearby is In
the Shadow of the Tower 2 and if you're looking to extend your
walk there are other caches nearby. This cache is also somewhere on
Leith Hill, to find out just where you need to solve the
puzzle.
The cache contained a working pen when I placed it but it may
have vanished or run dry, so I always advise to bring your own
writing implement.