I have been running through my code and comparing this against the documented sources on github for for the BBC and C64 versions and in doing so had uncovered some duplicate variables (i.e. different labels for the same location) and through debugging uncovered some issues with code & data overlaps.
With these resolved a number of things have fallen into place and with some tweaks to the keyboard code mappings other elements such as buying & selling cargo can also be used.
Annoying bugs such as the flickering crosshair and space-station non-visibility / projection issues have also been fixed and a shout out to Mark Moxon (of the BBC 'deep dives' fame) who has kindly offered to help, e.g. he fixed the issue with the starfield rendering incorrectly.
Still much to do, e.g. check the Missile and ECM systems work, look at triggering missions, sort out the ECM and Station proximity indicators, add sound effects & music and who knows what else!
But all in all a great milestone to finally see this game allow the user to play a session on our beloved Atari 8-bits!
Until next time, take care!