Check your warranty paperwork (it should come with all the handbooks and paperwork you got when you bought the car) and see what it covers, as not all manufacturers have the same warranty cover. If you're still not sure, contact Vauxhall UK customer services - their details will be on the Vauxhall website at www.vauxhall.co.uk. This does sound like something the dealer should be able to sort out easily and under warranty.