I have found this forumla for calculating the Offset, which was in this link:
http://www.skyandtelescope.com/howto/diy/3306996.html
The formula is:
Offset = (secondary size)/(4*focal ratio).
So for my 16" f4.5 scope, which has a 88mm secondary (I think), the offset should be:
Offset = (88 )/(4*4.5) = 4.8mm
That would be offset towards the primary I assume (axial). So as all my reading is indicating the offset is small.
Does this make sense?