If anyone is interested I managed to fix this issue, here are my findings:

1) Originally i must have missed the aspect ratio option in 'SET" via the tv tuner
2) regardless this should not have changed the whole head unit to be stuck in 4:3 aspect, this is a separate issue
3) when trying to re-code the NAV i selected Euro in Navcoder and this actually removes the option to change the aspect ratio in the 'SET' menu via TV Tuner
4) once i set the NAV back to australia the Aspect Ratio option re-appeared and i was able to set this correctly
5) I then changed it to Europe to remove the startup warning again and although the aspect option is gone again the TV Tuner has stayed in Widescreen mode

that was fun, hope this helps someone else