laguna alarm immobiliser

having a problem with a laguna 2.2 diesel alarm immobiliser it keeps goin off and flattening the battery. anyone know how to disconnect it without taking the car apart ?
i am a techy but renault are not the normal car i work on and trying to get info off anyone from renault is very hard at best.
the car is a 1996 model so i suspect if there is any known faults and repairs it should be easy to solve
all help appreciated thanks