Thanks guys for your input, though I don't think I'm going to make any drastic changes. This tune is one which I've fought with more than others to get it right. I don't want louder drums in the verses, the high hat and snare are where I want them to be there, in terms of volume, but they are a bit obscured by everything else in the choruses, and perhaps bridge.
I will probably bring the guitars down a bit in the choruses to let the drums come through a bit more.
I prefer the song without chorus harmonies, I've experimented with that, as I do with most of my songs and usually end up leaving them out of my mixes. In fact of the 12 vocal tunes of the 14 total, only 2 have harmony vocals.
Maybe I'll try a bit of piano rhythm - just in the choruses, no way do I want it in the verses.
Steve, as far as " placement of individual instruments" I've gone with the tried and true mix method of having instruments either 100% left, 100% right or dead centre for most instruments, with their respective reverbs being on the opposite sides. So all my mixes have rhythm guitar on the left, lead guitar on the right, snare, vocal and bass drum in the centre. Though I have deviated from this with the bass and high-hat, they're about 25-30% to the right - they seem to sit better in the mix his way.