My 03 has been fine so far.
It only went off when i was jet washing it.
Its a temperature related problem on the interior sensors PCB....wait until the winter comes Seany......Alarm goes off once it drops below freezing (don't ask me why..)
I'd go and get your PCB changed for the new version before the winter arrives and you have to run outside to keep switching the alarm off.
A quick fix is to....
1) Get out of car.
2) With door still open, lift door handle and then, with the handle still raised, push down the door 'lock' button.(as if you were locking the door from the inside)
3) Keep holding the door handle and shut the door.
4) The alarm will then set automatically (indicators flash) but isolates the internal sensors.
It leaves the inside of the car unprotected, but at least nobody can drive your baby away.....and it stops you having to get up in the middle of the bloody night