Hi Peter,
As a newbie to recording/mixing I don't feel qualified to comment on the mix, but, as a lifelong Heavy Metal fan (it was called 'underground' in my youth), this is up there with the best of them.
I really enjoyed the 'relaxed'? smooth style of playing and the harmonics of that guitar are beautiful. The interplay of the guitars in the last 1/4 was particularly enjoyable.
The beginning made me think that Black Sabbath was about to play and just over halfway through I thought Uriah Heep had just walked in! :-)
I really enjoyed it and after listening to it 4 times now I picked up something each time that I hadn't 'heard' before.
Great stuff. More please.