if i don't lock the car after starting the car the vibration from the plastic bit that pops up from the doors is very noisy can this be fixed all do i need a new central locking kit
By "vibration" do you mean the actual lock button or squib is being electrically forced to "vibrate" by the central locking solenoid or is is just loose and shaking?
the actual lock button is vibrating
You'll need to remove the door trim to inspect the actuator (which forms part of the door lock mechanism - check if it's loose or otherwise damaged and also check the wiring connectors. To replace just get one from a wrecker although the vibration may just be caused by a loose control rod which you can fix. You may need to drive the car with the trim removed to rty and duplicate the fault.
Search the "how-to" section in the forum for the details on pulling the trim off.