Is there a franchise requirement on GWR▸ to display a poster at each of their stations with train departure times from that station?
Here, on page 119:
1. Publishing the Timetable
The First Timetable
1.1 The Franchisee shall publish on the Start Date:
(a) the Timetable:
(i) at each staffed Station, by making the relevant information available upon request and free of charge in one or more booklets or in other similar form;
(ii) at each Station, by displaying the relevant information on information displays;
(iii) at each Franchisee Access Station, by providing to the operator of each such station the departure and arrival times of the Passenger Services that call at each such station and the principal Connections to any other transport services relevant to each such station in the same forms as are specified in paragraphs 1.1(a)(i) and 1.1(a)(ii); and
(iv) on the Franchisee's website; and
(b) the timetables of other Train Operators at Stations, in accordance with paragraph 1.4.
It doesn't actually say "poster", but comes close.