Thanks to Pokletu Staktu in this thread, http://p223.ezboard.com/fshoguntotal...icID=500.topic, there is a fix to the spinning camera in free look mode (when you press mouse button 4 the camera spins continuously anti-clockwise).

If you are running with a battle resolution in 1280x1024, then change it down to 1024x768. This should fix the problem (although you are running at a lower res, which is a shame). This is obviously a bug in the game, but at least we have a workaround.