Okay, the alarm is still going off, and now it's not just at night. It happens during the day as well. The alarm sounds for about thirty seconds and then stops mid-bleep. I can hear a front door closing at the same time. It sounds like the alarm is going off as soon as the door is opened, instead of just the usual quieter warning sound you get when you need to key in your code. I keep dashing out, trying to find out which of my neighbours it is, but it has always stopped by the time I get out! Clearly someone's system has a fault - but this has been going on for about six months now. I get woken up most nights with it, still.

To add insult to injury, there has been another alarm going off at night - one of those high pitched ones that you get on commerical buildings and sound when an alarmed door is open. I suspect it might be at Forest Hill School.

Maybe I'll just have to resort to having a afternoon nap until I can track down the culprits!