Alarm Conclusion

After loads of stress with the Alarm, it has now been fixed.

I posted on Brick-Yard and T4forum with a plea for help as my alarm kept going off. I was reluctant to go back to original installer initially after getting a bit of misinformation. However, he heard about the problems via the blogs and offered his services to get it sorted. It seemed the system would go off after being left for an hour or two. This could have been for 2 reasons:

1. VW 'brain' sending out a self-check system through the door circuit, triggering alarm
2. Faulty door switch (maybe corrosion causing small voltage on door circuit triggering alarm)

The first thing the installer did was isolate the alarm from the 'brain (i don't know the correct terminology!). This seemed to work, we left it for 2 hours with no false alarms. Unfortunately when I returned home, the vehicle did still trigger.
This means I have an issue with the door switches.
The installer kindly fitted new switches in the cab and side doors and connected the alarm to these. This solved the problem.

Its a little worrying to know my door switches are a bit 'iffy' but they seem to work fine in every other way (interior light, central locking, dashboard light etc). Hopefully I won't have an more problems.