James,
Interesting tune + David done a good job in polishing this! Definitely a big step in improving the mix.

P.S. James, a random question... are you using a pop filter on microphone? If you do, I would like to share a technique that might improve your vocals on recording. Try to "double" on the filters. Meaning sing through 2 pop filters (one on top of the other). It will get rid of most "plosive" sounds and ssss. It helps me in certain situations...
From the mix, it seems David was addressing these issues quite a bit. If you do not use it, I think it might be a good idea to get one (or two). They are not expensive things and worth every coin.

Thank you for sharing!

Misha.