Could try a scrap/breakers yard as the astra is a common car and chances are the electronic control unit will be available at a fraction of the cost of a new one but before rushing out to buy one ensure it is faulty. I once had a rover car and everything pointed to this item but I removed the unit and asked the local Rover dealer to test it and it was alright. In other words sometimes only the dealer will have the equipment and expertise to test these units.
sparky
April 2006