by any chance do you chuck your keys down on a shelf, or in a bowl when you
come in doors after parking it up,
I ask this because I used to chuck mine in a bowl with lots of other keys,
and occasionally I would go out in the morning and the car was unlocked. I
put it down to the remote button being pressed as it drops in the bowl.
I now place them on the sideboard and it has been fine ever since.

GGJ

Hi Bryan,

The central locking will fail-over to and unlocked state if one door
isn't closed properly and failed to engage the deadlock.

Try locking the car with the key fob then pressing the 'lock' button
again within three seconds. This will lock the car without deadlocks.
This will give you an indication of whether it's a dead lock problem.

After a recent trip to the tip I found some crud in the boot lid lock.
Make sure this is clean on your car as it would prevent the boot lid
locking properly.

Other than that, five minutes with some WD-40 on all the locks etc would
be certainly worth while.

Other than that, it could be an electrical issue but at this stage, I
doubt it.

One other thing, maybe the key fob has an issue. Try moving it well out
of range of the car at night.

Rich