You could try the battery just pull the neg off for 30-60 minutes. The radio doesn't have a code its VIN locked to car just make a note of all your settings.
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.