page 25

i’ve been collecting photos of the posters in paddington station which all seem to have page numbers on. The posters are usually huge (A0 sized ?) so they must be from a very big book.
however, this one was A4 sized (‘legal’ page size minus a bit if you’re not from round these parts). what can it mean
https://www.funkypancake.com/blog/stuff3/2006/05/DSC09663-thumb.jpg