My front door has the usual sensors - one large one attached to the door frame with the little blue light and one smaller one attached to the door. The small one is very loose and I'm afraid it going to fall off eventually (the one on my back door is solidly attached, so I know that the front one isn't right). Can I remove the little sensor (magnet) without triggering an alarm - I think it's screwed from the inside (??). How can I remove it as the cover seems solidly fixed.? I don't have the engineer code so is it a case of calling him in? Thanks for your help.