Cheers Mike, Steve, Christopher & Colin for the good vibes
Colin, thanks for your thoughts - It's unlikely to be tilt as it's entirely screw threaded system with the correct spacer in place.
I'll take a look at AutoPano Gigawhatsit, maybe theres a trial version - I really dislike switching between OSX & Windows so I'm looking for an entirely mac solution as the priority - and I'm holding off on Pixinsight as I use PS everyday
Clear skies tonight so back to it then...