Central Locking Erratic

My central locking has been very erratic this last 6 months. 
I’ll unlock the doors and then it would lock itself again a few seconds later. At first it was occasional but then became very frequent so I have been careful not to put my keys down in the car when loading etc. BUT weirdly this issue has ceased over the winter cold spell. To me this suggests a capacitor is not discharging properly and the cold has reset it. Has anyone else experienced this issue? Is there a module that needs replacing somewhere?