Have changed the battery in the remote control and now cannot use it to unlock/lock doors. Have tried all the suggestions on the forum but they don't seem to work. Also don't know where the remote receiver is as have taken interior light out in the headlining and there is nothing there. Any help would be appreciated.
That's pretty much what has happened to me, although my central locking wasn't working before I changed the battery.
I've had most of the interior trim out of the car to solve the leaking problem and on my way I've been looking for the sensor. It definitely isn't where the light is above the rear view mirror and I can't find it anywhere else!
To answer your battery question, it takes one battery and there should have been a type on your old battery, I think it is something like CR220 although I can't say for sure at the minute as I don't have my key handy. I'll post the exact type here when I have my key.