New Member with Sat Nav problem on a Navi 4.0

[Mach59]

Hello

I have a 2019 Insignia B and I am having a problem with the Sat Nav. I get a message "SD Card not inserted" or "General inaccuracy". I did have the SD card  module replaced under warranty as there had been a spillage before I bought the car and there was some corrosion present. The car is no longer in warranty and the dealer wants £120 to run a diagnotic and a local specialist £72.  I have scoured the forums but cannot find this issue related to the Insignia B only the A. Is anyone able to shed any light on this issue? Thank you in advance.