Weird Noise South East England August 24th 2011 (Audio Only)

The link below will show you every train station in the South East of England. I’ve posted this image as some plonker in the comments says there is nowhere in the South East that is 40 miles from a station! They are wrong. UPDATE - December 2011: All investigations and possible explanations of this event ran dry. There was one possible lead to the cause of this sound which led to a food processing factory 11 miles away. However, after s