I've got a Mazda 6 hatch (2005 model) as my commuter car. Initially it only had one key - with a separate fob to lock/unlock the doors - but I have now been given the spare, with an additional fob. The spare key starts the car - but the fob is dead and won't lock/unlock the doors. Is it simply a case of replacing the battery in the fob? Or does it have to be reprogrammed? Do I have to go to the dealer for this or can, say, Timpsons fix it?