Cobra Trailer front access door ....

I have a metal top Cobra trailer. The front access door latches just fine but there is a lot of play with the door and I can see wear marks on the side. Also I know of two pilots that have had the doors open and rip off while moving.

Has anyone added a 'safety latch' to the access door?

I am thinking about a hasp latch like this one http://www.stanleyhardware.com/detai...-hasp-s511-250

Or a barrel bolt type like this http://www.grainger.com/product/BATTALION-Heavy-Duty-Barrel-Slide-Bolt-WP157663/_/N-mf6?s_pp=false&picUrl=//static.grainger.com/rp/s/is/image/Grainger/4PB93_AS01?$smthumb$

I know that locking the latch will help but I do not know where the key is and I am looking for a more durable solution.

Thanks in advance

Ron Gleason