The LNER Encyclopedia

Hi folks,
I am hoping that somebody can shed some light on this van (I have photos of a couple of others) which has a large removeable board that slides from above into a frame. My best guess is that it was a large label board of some sort.

https://cumbrianrailways.zenfolio.com/p768193663

Happy to new year to all.

Thanks in advanc,
Stephen

Can you give a reference for the photo, Stephen? Your link opens a page with literally hundreds of pictures.