RobCrock, it all depends on if there is sufficient adjustment left on the forward pressure screw when the boot length adjustment is at it's shortest - I think that there should be but I've never tried it myself so please let me know how you get on.
The forward pressure adjustment is the smaller screw in the rear of the heel piece underneath the large DIN adjustment screw (see pic). It's purpose is to allow for variances in boot sole lengths that differ from those stated on the boot length scale. It's correct adjustment is CRITICAL as the binding will only release at it's stated DIN setting when the forward adjustment has been correctly set.
Correct adjustment is when, with the boot installed in the binding, the head of the screw is flush with the face of the outer housing (as in the pic). Any adjustment of the forward pressure should be done with the boot removed from the binding to avoid overstressing the screw.
When such a small boot size is mounted 'on the line' (on either the forward or central position on the Neox) is likely that the mounting position will still be too far rearward to properly pressure the ski over it's sweet spot. I'd therefore recommend cheating the boot length scale by keeping the toe piece forward & bringing the heelpiece forward. The boot lengths shown in the windows in the grey 'switch piece' won't be correct but as long as the two lengths shown when added together & divided by two are within 5mm of your actual boot length you'll be fine once the forward pressure has been adjusted. On a boot of your length I'd be looking to position it so the boot mark was at least 40mm ahead of the forward mark.
Here's some more Neox info including full instruction with plenty of pics:
http://www.jonsskituning.co.uk/content/view/35/50/