I tried the handbrake thing today, nope, not that.
I have had the car for over 2 years now and never once has the car made a sound when either locking or unlocking eg chirps from the alarm. I've never actually heard the alarm.
I don't think it has an aftermarket alarm that I don't know about coz the person I bought the car from was the only owner and he kept reciepts for absolutely everything he bought.
Its obviously nothing serious coz I'm sure I would have noticed, its just confusing.