We are in Nottingham and expect variety of clientele but probably not many railway experts although if word gets around who knows? Cost will be the limiting factor so probably more repo than original.
Funny thing that you are in Nottingham - I remember, almost 50 years ago - sort of 1970-71, there was a railway themed pub in the Victoria Centre - in a cellar. As you went down the stairs, there was a nameplate from Sherwood Forester (google 46112, Royal Scot class - it was a Nottingham engine around 1959-1961 time) screwed onto the wall above your head. I always assumed it was genuine - though the pub itself was rather faux, done out as psuedo compartments.
Well, as deltic has said, you can find all sorts of imitation stuff out there. I'm sure a certain kind of clientel would be happy with that, though personally I'm the type that would give it a look, but not too seriously. Given that Nottingham has a rich railway history, I'd try to make contact with some local groups, and try to get some genuine photographs of railway development in the area (you cou keep it to sort of Grantham - Retford - Sheffield - Derby - Leicester - Melton Mowbray kind of geographical area.
But even in Nottingham itself you had the Midland Railway/LMS, the Great Northern-Great Central/LNER. You had a zillion lines in the Nottingham-Mansfield - Trent Jcn triangle. You've got the dieselisation of the Midland from 1960-65, After the closure of the GC and Colwick in 66, and loads of closures and rationalisations into the 80s. But you've also got the reopening of the Mansfield line, and stations on the Erewash Valley, starting with Mansfield & Alfreton Parkway in c 1971 (?). The arrival of HSTs on the Midland in 1982. And the development of the Nottingham tram network from about 1990.
So there is stuff that both the hard enthusiast would like to see, as well as local 'normals' from the surrounding areas, some of whom would remember these events.
A lot depends on how much time you want to invest in it - but you could try to contact the GC people at Loughborough and the Midland Railway centre at Butterly
http://www.midlandrailway-butterley.co.uk/
Maybe the folks at Matlock too. Indeed, there is serious heritage railway stuff all around Nottingham (well, Loughborough, Matlock, Barrow Hiill, etc) which probably deserves some photos.
And there must, I suppose, be some serious railway society meetings in Nottingham itself.
Ask around - you might well get some people prepared to lend you photos or 'simple' railwayana like tickets on display for a few months at a time who'd be happy to see their stuff on the walls. I presume it would have to be well secured, however, given the light-fingered habits of certain folk.