Thanks for the feedback rayc. I'm going to re-record the chorus without the "chorus" effect and use the same reverb as in the verses, so hopefully that will help. Any ideas on how I can improve the mids?
I put the drums, bass, strings and main vocal in the centre on this mix with everything else panned left or right to some degree.
Do you think that it would help to lessen the muddiness if I moved the strings from the middle, or should I move the bass and drums slightly to the left or right?

For me, it's still work in progress when it comes to mixing, but I've always placed the drums and bass in the centre on my previous recordings.