bosch cond drier lower flap problem

Bosch condenser drier WTL6506gb/02
what do I need to make the condenser cover flap under the door shut properly. I have replace the flap itself as the hinge plastic bits had broke but still cannot get it to close properly. there is a metal bar inside the front with 3 catches to lock on to but these dont seem to stick down far enough, is there a spring or something? Have looked at the exploded but its unclear.