Central locking activates by itself!

Hiya,

I have a 2004 TD5 90 CSW. Recently it's developed a tiny snag whereby the central locking activates by itself when the door is shut.
I can unlock it using the door latch (inside) or the key fob (outside).
Sod's Law says it's only a matter of time before the central locking activates when I'm outside the vehicle and my keys are inside.

Any ideas, please?

Many thanks

Get a spare key and keep it outside the car.

That's Landrover for you!!