Thanks for the support everyone. My husband (he bought the camera for me) has talked to the retailers this morning and is taking it in to them today. He'll be pushing for the camera to be replaced, given the fact it's still very new, so I'll keep my fingers crossed. That said, I have accepted that it may be sent to Canon NSW for repair or at least assessment to prove the fault, and be gone for a few weeks. Lucky I still have my trusty little 450D.