Before the evidence, some disambiguation

Screens were everywhere in medieval churches, especially the larger ones.

One of the problems on the NLM thread is that we were constantly trying to be clear what type of screen we were talking about. I'm therefore going to give you a list of my understanding of all the screens that one finds in medieval churches. What's really frustrating is that in many places most of these terms are used interchangeably with each other and with terms like 'quire screen' and 'organ screen'. I'm tempted to refer to screens by these numbers in future to avoid explaining myself a hundred times!