driving

How to replace a 2000 Astra car key battery

My car key remote went flat. This is a major pain when one is used to the joys of remote key locking. Having to go to the door with the keyhole every time and fumble to get the key into it -- bleuch. I assumed that like most things in the world of cars, I'd have to take the key to a dealer and get some kind of specialist to open it up and replace it with a non-standard Holden battery not gen