i think it can be very powerful to use this music as inspiration or a backdrop or simply as space / vibe. but maybe too much of an overt association would be too close to, like you say, "cliche" territory. i personally would try to evoke those moods without too much, if any, mention of the music. anyone read the book from which Children of Men was adapted? does it mention dubstep at all?
I agree. I think that pushing it too hard is wrong and would be dry. Music is generally a sideshow in books and I like it when it's mentioned as it somehow concretes and adds a layer of sensation ( for the same reason that I like reading about food in books)
But there is a deeper sense to Grime and Dubstep. Like mms said, an intensity and tension that resonates and lingers. Maybe it's something to do with the bass driven nature of it, it always seems to be leading or pointing to some emotion or lost memory or something...it's hard to get at just what.
I definitely get your Children of Men reference. It has that wet and sorrowful feel, and it's full of weird happenings and loss. Did I hear from somewhere that their is a dubstep tune being played when the main character enters the pub. I'm sure their was a Dubstep reference...?