Ok this one is more for me so I can remember what I did next time!
Basically the story is I have a monitor attached to a computer running Ubuntu (Minimalist) via a 20m VGA cable. The monitor is mounted on a wall and rotated 90o
clockwise. It is also a small widescreen so has a strange resolution. When I connect it to the computer with a short VGA cable it is fine and Ubuntu picks up the details, however with the long VGA cable it doesn’t so puts on an even stranger resolution.