If your management light is on, you should be able to get a code(s) using an obd2 reader. This might relate to the issue with the display not working but still showing orange when the car is off.
Obd2 readers can be obtained from many sources on the internet, and range from just a few pounds upwards.
Once you have a code(s) depending on the reader, you will be able to find d out what this refers to. If you post the code on here, there are members that will be able to help with the meaning of the code.
It might be that the management warning is unrelated to the display fault, but at least its a place to start.