Ok normally the procedure is as below..
Sit in the drivers seat with all the keys and all the doors shut, radio off, no lights, everything OFF
Insert a key into the ignition
Turn ON the ignition
Press and hold the LOCK button on the key for TEN seconds
Turn off the ignition and remove the key
Insert the next key and repeat the procedure
WAIT 1 minute, do NOT switch anything on.
When the 1 minute is up, open the drivers door, exit the vehicle, close the door
Test the keys each lock and unlock the doors.
If that fails to work then try reseting the BSI as below..
Open the drivers window and the bonnet.
Close all the doors, switch off everything, like the radio, phone charger etc.
Remove the ignition key via the open window
WAIT 10 minutes
Disconnect the battery.
(change the battery at this point if this is required, otherwise WAIT 30 seconds)
Reconnect the battery,
WAIT 1 minute
Keeping the doors closed, lean in via the drivers window
Switch on the 'ignition' (Don't start the engine)
Switch on lights (Dipped, normal driving lights)
WAIT 30 Seconds
Start the car / switch off and check central locking
So as above give those two procedures a try