Nearly finished, I just need confimation of a couple of answers as I don't understand the wordplay.
40across: Canals join it in places (6) _N_ERA (I assume it's entera)
31 down: Quickly I start to mix up an agent that causes pupil contraction (6) _IO_IC (I assume its miotic)
Could anyone confirm I'm right or wrong!
Thanks in advance
P.S. Really enjoyed this one - very clever!