Wednesday Night Klub Run (WNKR 2014) - a bit like TNRC but not on a Tuesday

From the Little Berkhamsted website(!)

The most notable landmark is almost certainly Stratton’s Folly, a Georgian prospect tower built in 1789 by John Stratton close to the site of a former brewhouse. Although the reason for building the tower is not known, stories that Stratton was an admiral who wanted to be able to see his ships moored on the Thames are certainly nothing more than fiction. Most likely Stratton simply wanted to enjoy the views offered by this folly.

It's listed (full details at English Heritage)

Traditionally built to view ships on Thames but more probably for astronomical observation.