Chiming after locking with fob
 

Hi, about 30 seconds after locking my wife's 57 plate Mazda3 with the key fob, the car starts chiming. The chiming stops after I press 'unlock' on the fob. When I lock it again, the chiming starts again.
So the fob works...the glovebox and ashtray bulbs are fine, the lights are all off, but the chiming continues.
If I use the key in the door to lock the car, I don't get the chiming...it's only when I use the remote locking on the fob (not an advanced fob):crying:
Help!!!