I have the opportunity to drive to the East of England Showground at least twice a year, and every time I pass this building, I think, "That's odd, there is a railway station totem on the side. I wonder if it is a real railway station?"
A few weeks ago, I remembered to find somewhere to stop and bag a photo to remind me to do some research.
The answer to the "Is it a station?" question is - Yes.
Or if you'd prefer to have a look around for yourself: