That is really nice, and I'm glad it landed with someone who knows what it is.
I had a Nottingham Triumph at one time, bright red. That was the only thing fast about it, but I bought it from CL, the guy was 70 or so, and had a beautiful 34 Ford Coupe. It was all Huret and had steel rims, like new, and those leather straps on the hubs. I took it to Stop/Swap/Save and sold it before I got into the show to the Bike Man from Delaware. If it had said 531 I'm sure I'd have remembered.