beep on start up?

My 197's alarm randomly beeps. I haven't pin pointed what i'm doing when it does it. The other day it seemed like it was because I pressed the lock button on the card quite a few times. When I first had the car I just thought the alarm beeped all the time, bt it stopped doing it after a couple of days. Apparently this happens if the alarm system has been activated. I don't think it had though, so i'm not 100% about that. Mine has never beeped inside the car apart from when it needs fuel or the hand brake is slightly on whilst driving. Oh and the seat belt and doors!
 
yep double beep from mine when i open the door, sounds like the alarm or something