I'm feeling weird about this one.
I think that you've got an alright arrangment, but the drums are pretty weak IMO. DnB is about the Drum and BASS!
The kick drum needs more punch which I think can be accomplished by boosting up around 200hz or so, or at least in some of the midlow freuqies. The drum lines are really cool but they should just come up.
I agree there is a huge swath in the middle of this mix that could use instrumentation. Perhaps give the bass a bit more in the higher register of frequency information. Make it a triangle or a saw instead. I'm not great at synth design, but those are some things to consider.
that's what's got me buggered the most. <3