hi

have you tryed to start the car as some times the lock breakes the bit that goes into the switch and you cannot switch it off or on you can get the key barrel from vauxhall

If you read HJ's review its states that the ignition barrell can become faulty and basically fall to bits, Requires new inginition barrell + labour a near £500 jobs. This could be a cause looking into as they were made from cheap plastic.

I would take it in, The longer it goes on the worse it could get.

hth michael