On a My Travel A320 last week the flightdeck door opened during the deceleration after touchdown at Beauvais. Same aircraft returning at the weekend and exactly the same thing happened on landing at BHX!
Didn't seem very secure to me if that's all it takes. Probably could have pursuaded the door open with a nudge of a foot. Is the policy to lock the door during takeoff / landing? If so, the locks aren't terribly good!