locking or door

First off, forgive me if this has already been posted, but from the searches I've done it just seems to be people asking questions about the interior sensor button and various scattered info about the alarm system etc... thought it would be better to have it all in one place! Well, I've just...

Tried searching and found no certain answer. My central locking is playing up a treat when i get in the car start the engine the door lock straight away then i can constantly hear the system trying to lock again even tho its already locked, the switches to lock/unlock doors on the trim dont...