My VY SS has been off the road for a few months due to the alternator being stuffed so obviously the battery hasn't been connected. So,I have just got it back on the road and the alarm keeps going off randomly, all the doors are closed properly also the boot so it really doesn't have a reason for this to be happening and this has never happened before.
It could be either the Drivers Door Lock, Drivers door Switch, Bonnet switch, Just to name a few Maybe get is scanned to see if there is any history events that may help with diagnosing the issue.
Classic Symptoms of voltage drop, like losh said charge up the battery or replace it as it may be stuffed.