How do I disconnect my alarm - Renault Laguna Estate?

Hi there, I have an "S" reg Renault Laguna Estate 1.6 however dopn't have the central locking keys or alarm fob. Every now and then my alart will just start going when I open the door. I can't seem to turn this off, however can still drive with the alarm and lights going. I have been unable to find any way of diconnecting this.

Please help...