Have you phoned the previous owner to see if they have it?
If it has the original Vauxhall nuts the tool number might be on the "car pass" card. You might be able to get the details from a Vauxhall dealer, but they will probably charge you.
You can buy tools like these -
http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10151&storeId=10001&partNumber=696823&langId=-1&cm_mmc=Googlebase-_-Workshop+%26+Tools%2FSpecialist+ToolsX-_-Na-_-Laser+Locking+Wheel+Nut+Remover&%24%24tid=0-4NfKru7zJHfzHQ9YPcScNidaEHp7BZfHgQOCIJ2myq66qDSs_lR73GcF_YpJ1f
or
http://www.avenue35.co.uk/shopping/shopexd.asp?id=37348
or
http://www.lockingwheelnutremover.co.uk/indexEnglish.html
or call out the AA or take the car to a garage, tyre fitter, kwik-fit etc.
Whichever method you chose you will wreck the locking nuts and have to buy new ones.
spenny, November 2009