Hi guys. Just thought Id throw this in… I was driving back to Cambridge from Northampton, on the A45, when I was betweenEarls Barton and Wilby roundabout, I narrowly missed colliding with a trailer door that had come loose, or been opened and was swinging well into the carriageway. I dialled 101 and called it in, but the operator said it was being dealt with imminently.
The message has to be, try and make sure your trailer doors are secure before you go to bed. I know no ones infallible, but it really is dangerous, and dont get me going about overnighting in laybys anyway… 
Simple fix. Carry a padlock; if you have to park in a lay-by, open your nearside trailer door, padlock offside one shut so no scrote can undo it and leave it dangling.