This is not normal behaviour for the alarm. Here are a few quick and easy things to try if the issue persists:
Lock and unlock the campervan using the physical key (not the key fob).
Start the engine - this often resets the alarm.
Check that all doors, the boot and the bonnet are firmly shut.
Move the key away from the campervan for a minute, then try unlocking again.
If you've done that and the issue continues, especially if you’ve also replaced the key fob battery, it could indicate a faulty door sensor. In this case, the campervan may need to be checked at a workshop.
Contact Roadside Assistance (available 24/7) so they can send you to the nearest workshop. Any time taken out of your holiday to visit a workshop will be reimbursed, see Our Promises for more info.