This is exactly what I'm thinking. I'm thinking along the lines of, alarm gets armed, some time later a door contact shorts to earth and the interior lights come on, the alarm sees the voltage change and off we go again waking the neighbours up!!!
I have now been and checked all the push switches. The rear nearside door ( it's a five door BTW ) switch attachment screw did seem rather slack but I'm not sure that would cause a prob. Rear offside was covered in fluff but again same applies.
I've also had the passenger footwell panel off and have made sure everything on the alarm module is fully plugged up, it was dry too, no damp anywhere there.
I'm going to plug the standalone sounder back in during the day over the weekend to see if the problem is still there.
Can anybody add anything about the the MFU and test mode please?
If anybody can add anything to this, even if they think it may be trivial, please speak up as you may hold the secret to this mystery.
Cheers.