Mostly printed CNC IE extruder holder

this is my first attempt for the "M P CNC"
I am in the UK so doing the IE version, but couldnt find a 3d printing extruder holder .
i havent built my yet so if anyone can tell if this is not correct i would be grateful.
I have set the mounting holds at 30mm so will take a greg/wades or with the wright mount mk8 (http://www.thingiverse.com/thing:723656)

any input good or bad most welcome