[glend (Glen)]

Well Dunk, this is a new scope right? I would start with some basics, like making sure the secondary holder is properly centred in the tube, ie all the vanes are identical lengths and the centre lock screw is exactly in the middle. Check the vanes are vertically aligned in the tube, some can be tilted if they are just held by a screw through the tube wall. Also don't assume your laser is in fact properly collimated, i recommend checking that by rotating it in a jig. You want it to stay within a circle of 10mm over say 4 M.
Don't mess with the secondary offset, just yet, it should have been set ok at the factory. Read Astrobaby's paper on Collimation and secondary offset.
I don't know anything about that coma corrector, i use the Baader MPCC and never have a problem (it uses 55mm backfocus). You should be collimating without anything else on the scope, i assume that was obvious. Try sticking your DSLR on it, use Liveview to star test.
Don't over tighten the secondary collimation screws, this could distort the shape, ie = astigmatism. Also check the tightness of the primary adjustment and lock screws, sometimes they are overly tightened by the factory for shipping security . All of this can be done on a bench, or on the lounge, as long as its properly supported. Good luck.