I purposely name dropped the reasons I wasn't using Ubuntu natively in the hope someone would point out if it was possible or not
I enabled 3D acceleration in the VirtalBox settings, and Unity started working right away.
However now I have terrible frame lag when dragging Windows. I've tried un-installing and reinstalling the VirtualBox tools to no effect. I did notice that the few seconds between the script un-installing the tools, and reinstalling them the frame lag temporarily disappeared, hinting that the native drivers in Ubuntu may be a better way to go.
A bit of Googlin' around and I found this
Is that a different way of achieving the same result, or is that an alternate method I might have more luck with?
sudo apt-get install virtualbox-ose-guest-x11
Currently I'm going with a Windows approach to fixing it, and reinstalling the VM but this time with the video acceleration enabled from the beginning, not post install. However I'm fairly sure the mantra of reinstalling fixes all isn't so applicable on Linux