Mystery item needed

I have an intermittent problem with the central locking on my motorhome.  It occasionally blows the fuse and so far all attempts to isolate the cause have failed.  I now am concerned that if it fails whilst we are away I won't be able to lock the doors, thus making us very vulnerable!!

As an interim solution I am trying to identify a product, which I am sure I have seen somewhere, that links the cab doors together so that they cannot be opened from the outside.   As I recollect, it was a bar comprising two halves, with a hook at each end to go over the door handles.  You slid one half into the other to adjust the length to fit and the lock it in place.

Just wondering if anyone might know what this item is, or is it just a figment of my imagination?  Any help will be much appreciated.