I have just had the cars first service done at the vauxhall dealership that supplied the car, and guess what engine oil they used,Shell Helix 10/40 semi-synthetic, the service book says fully synthetic 5/30, upon asking,the service manager said this is the oil we allways use and its approved by Vauxhall, so i e-mailed vauxhall, not so they said and now your warranty is invalid because of the oil that has been used, but my service book has been stamped to say it has been serviced to Vauxhall standards.so i now have to go to the dealership to sort it out, i think this is fraud, what do you all think.