Partner HDI 2004 problem with Central Locking

[Mikedav]

Didnt drive the car for a couple of weeks and when I went to use it the central locking didnt unlock the doors, I had to use the key in the door lock to get in.
Car started OK
The fault also appears when trying to use the button on the dash.
The front doors do not lock or unlock with the c/locking at all and neither does the hatch door.
There is a very slight clunk from the back sliding doors, they lock but wont unlock via c/locking. You have to unlock from inside manually.
The interior light door switches work fine, if u leave your key in the ignition and get out of the car the warning beep works. The key fob can make the hazards flash from a distance as normal.
Once or twice I have heard a deep beep tone from under the dash when I tried to use the lock switch with the engine off but ignition on. Interior lights go out when doors shut after the usual time delay.
I have disconnected the battery and waited a few minutes before reconnecting but still the same.
Any thoughts?
Thanks
Mike