Megane 225 alarm problems........

[reidy]

Hey guys,ive owned my megane 225 for about 6months now its on a 54 plate and over the past 2weeks the alarm has decided to play up,when i lock the car after about 2minutes the alarm starts going off for about 20sec intervals then stops for about 5secs and then goes off again,this can continue between 20minutes and hours....ive tried normal locking,deadlocking,making sure the wheels arent locked,tried pushing the stop start 5 times thing and the fuses seem fine,so im a bit stumped,if any1 has any ideas please help as my last resort will be the renault garage as ive had problems with them before and dont trust them...Thanks.