Alarm issues

[hawker22]

Evening all , so as the tittle says im having some trouble with the alarm. Every so often ill lock the car and it will beep at me and then the alarm will go off a little while later. Other times it locks fine but about half an hour later will just start going off. It can be fine for a couple of months and then it will have a funny week or so where it plays up. Any one got any advice ?
Thanks in advance

 

[petercronin]

Check your bonnet alarm plunger bracket. They corrode and may have become misshapen enough to be just triggering.