Well that was embarrassing!
I was backing out of a parking space at the supermarket. I was most of the way out and blocking the traffic when I needed to go forwards again before reversing right out. But the gear selector wouldn't move out of reverse!! Looked down and found that the flexy blind (jalousie) had broken off and jammed on top of the bit that was left. it took a few seconds of frantic wobbling to free it so that I could move.
The blind had already broken earlier in the year, but only exposed a small hole at the back when in park, so I left it. This time a further short bit broke off and turned sideway and jammed cornerwise across the slot.
The original blind was replaced at the end of October 2015 after nine years use. This one broke earlier this year after six years. At least I know how to fix it now.