Under the Hornbeams'I'm not homeless: this is my home!' Nick points to the branches of the hornbeam under which we are standing, its leaves still glistening in the aftermath of the morning rain. On one of the lower branches sits a robin, joining our conversation. It seems to be saying: Why should anyone want to leave this place? Nick and Pascal live and sleep outside in central London. They are an unusual duo: Nick is an avid reader of history and philosophy able to