http://www.bmycharity.com/DenniSullivan
The Hero Walk is a very tough challenge over the high chalk downs and ridge ways of Wiltshire and Salisbury Plain. At 26 miles it forms a marathon for runners and a great challenge for walkers. This challenge is a diverse trek over marathon distance, going back through 6,000 years of British history.
Here is more info about the walk http://www.helpforheroes.org.uk/challenges-2011-avebury-stonehenge-september.html