The particular charm of the novelist A.L. Kennedy’s radio voice is not easy to decipher. Part of it is to do with her characteristic wryness. Rather more is to do with the tinge of melancholy – a peculiarly personal sadness, often seeming to exist at one remove from the subject under discussion – that marks her delivery. Looming up from the margin is the fact that neither of these qualities is especially common to daily life in radio-land, where the grey area that lies between the upbeat and the tragic is seldom penetrated and nuance of the kind in which she specialises can sometimes seem rather puzzling.Found last week imparting some thoughts on the perils of our obsession with technology, under the general title of Battling the Botnets  (27 June), Kennedy sounded