Back in the mix with a 2017 LWB (A few problems tbh - but for another post)

Anyway a minor niggle….
The rear entertainment screens work perfectly for whatever length of time until you turn the car off when parking or filling up with the diesel etc
Then when you get back in again and try to switch them on via the menu the error ‘Rear media it available’ is shown. Switch car on and off again makes no difference until the car is left locked up a period of time, next day usually , and they work fine again.

Any suggestions?