Hi DM,
Nice looking New Imp, but are you sure it's a Model 11B? The 11B was the "Blue Prince Deluxe" from 1931, but there are a few things about your bike that look more like a c1929 model. Chas Lipscombe's lovely New Imperial book has details of all the models. Have you dated it from the engine and frame numbers? A pre-1931 date means a ride at Banbury if that floats your boat.
Racing? New Imp did, but not with bikes like this one. It looks like the standard sports roadster, so it may have done a few laps in a vintage parade in the 1970s, but there is nothing at all that suggests serious racing.
What's your plan for it?
Cheers
Leon