Cameron McNeish’s new book, Come by the Hills, is published later this month, following on from the success of his memoir, There’s Always the Hills . In this extract, Cameron delves into the history and legends of one of Scotland’s most beautiful glens. IT was Sir Walter Scott who first described Glen Lyon in the above terms and my old mentor Tom Weir was fond of using the same alliteration to describe this 34-mile long glen of highland Perthshire. He often told me Glen Lyon was his favourite glen and for a man who knew Scotland like few others that…