UK Car Repair: astra remote door lock sensor, rear view mirror, door locks

Question
the remote sensor for the door locks on a 2000 1.6 astra has stopped responding. could you tell me where it is located so i can get to it and replace it please. i've changed the batteries on both the keys and to no avail.

Answer
I'm not sure where it is but, on most cars it is in, or near, the rear view mirror or the rear window. Have you tried programming it?  Do so by using the key to lock and unlock it with a few seconds pause in each position, then quickly lock and unlock with the remote.