Tambour Washroom Door Problem on Fairford

Anybody have a fix for stopping the tambour door on our Fairford flying open when we are on the road. 
The magnetic strip on door and frame doesn't seem to be strong enough, however gently we set off, accelerate or brake the door always slides open and usually slides off the end of the runners and jams itself. 
At the moment we have two bulldog clips with elastic band between, clipped to door and magazine pocket outside cubicle.

either you need a 2nd magnet or a more powerful, bigger one...
or...something physical (but prettier than) the bulldog clip...
in the menatime, id be looking at some form of stopper to prevent the door coming out of the tracking which must be a right pain..
good luck.

Thanks Chris, previous owner or dealership must have had same problem as have found pieces of cracked runner glued back in place just short of the end, have tried different stoppers the door just slides past them bending runner then jams into the ribs in tambour door. A rubber walking pole end is my latest attempt at a stopper and the trusty bulldog clips have helped. Can't source a magnetic strip of right size, to slot into door frame. Any ideas? Thanks Chris