Appreciate everyone’s time for their replies.
DzzD… Newb here, and downloaded OrcaSlicer (It looks same as Bambu, but sure it is not. Will have to investigate more).
What do you mean ‘Set a Correct PA value’ and what is the Gcode example you have shown for Linear advance?
Again HUGE thanks for the swift replies, like to get to the bottom of these marks as the other half of the box when printed does not have these marks at all??? Strange it is…
Thanks again, any help is always welcome for this noob!