Thank you ever so much for your kind comments and I really appreciate the advice.
You've both sort of confirmed a couple of thoughts I've had over where to take it next, I must say, particularly on the sub-front.
Last night I bounced the audio coming from the two deepest channels (pre-fx) to two new channels & applied 100hz low-pass filters to them both. Then I applied 100hz high passes to the source channels, giving a sort of 100hz crossover.
I then dropped the levels of the low-frequency channels a bit & lowered the frequency of the low-passes to about 80hz,
and this seems to have cleared up the bass frequencies quite a bit. (It all felt a bit too 'flabby' before)
This could indeed leave plenty of room for some sweeping sub action!
Man, nice idea!, that could really take the darkness of the growls to the next level...
(Have a look at 'Deep Space' by Sub-Focus on the spectrum analyser - they must have had some fun!

)
After that I could take the most successful sections back into the session view, and spice up the arrangement a bit.
I really recommend you check out the launchpad - it's brilliant for finding new layers and sections, great fun!
Then perhaps I could put the song back into a more traditional (mixable) arrangement.
I'll upload a new demo next time I have something together, thanks again guys!!!
Kindest regards,
N-e-b-u-l-o-u-s