Marty - similar boards used to hang at all the principal former GWR stations - certainly I can recall during my time on the railway (1992 to the present) seeing them on display at Plymouth, Exeter, Taunton, Bristol, Swindon, London Paddington, and Cardiff - they may also be at other locations. I was at Swindon a few days ago and don't recall seeing the board on display there - I guess it is possible it was removed during the extensive rebuilding of Swindon station in the 1970s.
As a general rule if thumb (but not always!!) the boards were displayed on, or very close, to platform 1 at the stations where they were displayed. The only location where this
may still hold true is Exeter St. Davids, although I have a suspicion that the board there now resides on platform 5. That said, I don't get to Exeter St. Davids very often and I can't recall where it was the last time I was there. At Paddington it may still be on Platform 1, but I have an idea it is now around the corner towards the taxi rank that leads up to Praed Street.
Cardiff Central is my local station - do you want me to try and get a photo of the board there for you?
