He absolutely loved all the Cherub books but for some reason he didn't finish the last one which I think was set in the second world war. Maybe I'm getting confused and it was a different series by the same author?
I just asked DS1 (15) what he would recomment. He recommends the Aragorn series, the Twilight series (yes marketed at girls, but he has read them all), The Curious Incidence of the Dog at Night-time and authors like Terry Pratchett, Garth Nix. He is heavily into Jim Butcher at the moment - he writes about a wizard PI in Chicago, although I think his books are in the adult section of the library rather than the teenage section.
Re Trainspotting, we have a complete non-censorship policy here. My feeling is that as long as he is reading I don't mind what it is - magazines, books, whatever, but it is up to you.