Anyone used a small strut to do this job? I'm now in need of the same fix
I think that in the limited space available, a strut would be a possible waste of space/ hindrance.
For instance, I sometimes fill my topbox with small packages from Bunnings as part of my job, and the flexible cord has been known to be pushed out of the box, creating a jamb hindrance. A rigid metal rod/ strut would be even more likely to foul on the contents. Often simpler is better.