Xantia alarm and central locking problem

[Edhertz]

Thanks for thread. Just like to add my bit here. Like you I've had several experiences of the alarm going off for no reason, strangely all late at night. Just come back from caravan weekend parked in a dark windy wood under dripping wet trees and it went off again at around 2am.....great fun! Faulty sonic sensor? Glad I'm not alone.