FL2 GS Audio system not working - what do I do next?

2013 Freelander 2 GS. This is the basic audio system with the small screen. There is no sound or visual details (e.g. radio station details) coming from the audio system. The screen shows the clock function and I can change audio settings visually (i.e. no sound). The cd player will accept CDs and the phone connects. Two fuses in the boot are live. So my question is what do I do next? My assumption based on the above is that it is the audio unit. that is faulty, but I am not sure. I dont think there are replacements for this unit. Has anyone had similar problems and what did they do? I usually have a plan when things go wrong but I dont know which way to go next.

A code read is the place to start.

Hi, Thanks for your response. I dont have a code reader and I assume that only a decent code reader would provide detailed information. Given That there would be a cost for this I wondered how detailed the info would be, i.e. could it differentiate between a failed audio unit and some other failure?

The vehicle is software driven, and so a suitable code reader will pretty much tell you what is wrong with it.
I've got several code readers, but I keep my Icarsoft I930 in the vehicle, as it's good at reading everything quickly. They cost under £100, which is about the same as having the codes read at a suitably equipped garage.