Automatic central locking problem?

When I went out today I noticed the auto locking at about 15mph wasn't working, which it has always done since I had the car from new. Testing the rest of the central locking inc the alarm everything else is fine and I've not been messing about in the maxidot settings which is wierd. Looking in the maxidot under convenience, central locking, door unlocking, under automatic both the lock and unlock options were not ticked, so I've selected them both which will hopefully reset things to how they were.

So my question is has anyone else suffered such gremlins and is it a sign of potential problems to come. I haven't got vcds so can't do a scan to see if there's any error codes.

cheers

Ade