Here’s a nice little video from fullflap.tv. It’s a short flight around North Kent and the Thames Estuary — pretty much where I grew up, so I know this area like the back of my hand! Starting from overhead Tilbury Docks, the C152 takes us across Gravesend and Brands Hatch, then via Canterbury and Whitstable to Red Sands Fort, out in the middle of the estuary.
You’ll find more videos like this on YouTube, and FullFlap.tv. More information on Red Sands Fort, and the outher Maunsell Forts can be found here.