Probably our motorcycle. Unfortunately, I could not find the original of the picture on the left, reproduced in Roy Bacon's "Norton Singles". It looks as if the silver on the petrol tank is the traditional Norton silver, whilst the chassis parts are a darker metallic grey. The Norton parts we have in original finish from those days- notably an instrument panel and an outer primary chaincase- are a darker grey than the petrol tank of our Inter, the paintwork of which looks original, and are most likely the grey the rest of the bike was painted in.
As first-of-the-line bikes were often photographed as templates for the highly-retouched sales brochure pictures, this is most likely the machine you see in its current state at the head of the page.
It must be said the bike looked far better in its original colour.