Thanks, Steve. I don't think I'll be playing with the laser collimation.
A search of the site came up with LaFey's drawing of his problem, which (the left hand one) seems to equate to the effect that I am seeing. It seems that the general consensus of the time was that is what one should see when offset is taken into account. In my case the 'cross hairs' are the spider's vanes.
http://www.iceinspace.com.au/forum/s....php?t=9436#12
For the moment I think I'll just ensure that the primary mirror centre spot (ring binder washer) aligns with the centre of the reflection my eye, the spider is centred and the laser tool indicates the return reflection is also centred in its viewing window.
It seems that I was worrying without cause. Thanks again everyone.
John