Panda - Radio comes on on its own

My dad has a Panda Dynamic from mid 2005 with a wierd problem. When it is parked up with ignition off and no key in the ignition and the radio 'off' (not mute setting), then after a variable time period the radio will switch itself on. Sometimes 5 mins after switching off, but at other time hours later.

(I've checked that the traffic awareness TA function is set to off but it still does it).

Can any one offer any experience of having had the same problem and how you resolved it?

Cheers,
Moz

For some reason fiats do this when you use the Remote or Centrall locking as it triggers the Power to the headunit. I dont know why but it should turn off with the Timers so the battery prob wont drain.