Following the disappearance of the Alphabox, I've decided to keep a geocache in this location, but unfortunately not home-built with a field puzzle. Since then, the information has been updated, and is no longer premium. A shame, but I hope to make some of my existing caches more interesting in the coming months.
The cache is accessible from the path that runs alongside the A10 but not the A10 itself; it shouldn't be treated as a Park and Grab - there are spaces to park available in the nearby streets.