Well, the mastering didn't go well with Andy Jackson and we've decided to go our separate ways.
I've since started using Brian Hazard at Resonance Mastering. I don't want to jinx the project any further but so far I've been really pleased: the communication has been excellent; some mixes weren't accepted because they needed a few tweaks frequency-wise, which subsquently I feel have resulted in better mixes from which to master. I'm a bit punch-drunk from the last eight 7-14 hour days' work (and yes, my ears are suffering a bit - I'm a fool) but hopefully it bodes well for the future.