Sorted.

Apparently if you have Switch 6 not in R/C mode then this effects the mixing.

I had it in this mode because this is the only way I could get the drive to fail safe. Something else I can't seem to get to work.

If I am in R/C mode when I shut off the Tx the motors creep forward and no matter how I try and adjust the trims, set the sticks on start up, or re-bind I can't stop it from happening.

Furthermore the lost signal shutdown never comes into operation, which would have me believe it is a problem with the Rx. Except it can't be due to what I described above about not being in R/C mode.

*brain explodes*