strange alarm issue

[Prime_PPP]

Hi guys just after abit of advice please. Basically my battery went flat the other night managed to jump start the car had a long drive to charge the battery. 2 Nights later flat again so replaced the battery now all fine.

Problem is now that when i press my alarm button it locks and the lights flash etc but as i walk away it unlocks itself again and has only done this since the battery went flat.

Is there some sort of reset i can do , i tried both the key fobs but they both seem to do the same thing so i thought it was unlikely to be a battery in the fob. Sometimes it locks fine , but this morning i came out and didnt press the alarm button and just tried the door and low and behold it opened , alarm went off still.
Any ideas whats causing this as its a little worrying , will book an auto sparky if need be , cheers all