Is your alarm on auto-arm or manual-arm? If it is set to manual mode, and you do not manually re-arm it after you park up, you may in fact be arming it as you get in to start the car, which can create all sorts of issues.

The only elements that affect the alarm are the drivers seatbelt and the doors/boot. Clutch, gears etc. you don't need to worry about.

I believe the brant alarm manual is stickied in one of the forums.

Could be worth having a read through and making sure you have it all set up correctly before trying to diagnose a problem that may not be there..