BigIan

I had occasion to use the sat nav in France recently and found it virtually impossible to read especially when using it in split screen mode showing the "list of forthcoming junctions" as the nearest, and most important, junction was shown with white letters on a light blue background. look at the lowest menu option. I've tried to change the colours from green theme to blue them but the nav stays the same. Does anyone know if there is a way to customise the colours on the display? thanks Ian