Overnight I fixed a few bugs that were stopping multi-colour text and bitmap mode from working.
Colour selection is now working correctly as can be seen in the following images. It is also clear that the machine is able to run increasingly complex software.
However as can be seen is some glitching going on in bitmap mode. I need to look into the cause of this. It looks like 3 physical pixels wide, which would suggests it might be a pixel pipeline issue.
Multi-colour text mode has been fixed as well, and has no bitmap related glitches.