"HMS Osprey’s former DISTEX site... Ship crews from Britain and various other countries would carry out exercises and riot training along this stretch of ground and inside the buildings surrounding it. A lot of effort went in to the exercises to make them as real-to-life as possible with casualties even sporting fake blood and broken bones."
https://www.theurbanexplorer.co.uk/east-weare-batteries-distex-site-portland-dorset/
http://www.geoffkirby.co.uk/Portland/695735/