Head units restarting 2008 FL2 TD4

Hi all I’ve recently started to have a problem with the sat nav unit and radio restarting while driving as if the car has been turned off then back on. The phone option on the car stops working. But if I disconnect the battery and reconnect after discharge then all back working again. Has anyone else had the problem and any idea what is causing it?
Many thanks in advance

It's probably the BT module. This unit is known to give those sorts of symptoms.