Just a quick (and possibly silly) question. I'm with O2 and have had my mobile contract for 23 months now. I can upgrade a month early next weekend but am wondering, if you choose to upgrade early do you have to upgrade directly with O2, or can you upgrade early via Carphone Warehouse, Phones 4 You etc? I want to stay with O2 but they do not sell the phone I really want but on the Carphone Warehouse website, I can get the HTC Desire HD on an O2 contract.

