Thanks for the response Raze.
I did try mirroring but this did not make a difference - it still crashed. Is it possible to do this once the game has loaded on the laptop? I will try later.
I will try the windowed mode fix you mention, but previously I could not get it to load in windowed mode - and I have to actively switch off the external monitor and docking station to make it work at all. So not sure how this will go!
Thanks
Dan