Martin from the UK sent another contribution; "I am now prompted to send you a charming little cartoon of a lad and the object of his fantasies, a flat tank Model 18... This was published in 1963 in a book by a well known journalist, Maurice Wiggin, and included a chapter on his motorcycling exploits in the twenties. I attach a copy of the picture drawn to illustrate the section referring to this fine machine, and also a scan of that page to which the picture refers..."
Do click and read the text, it sums up completely why you should own a flat tank Model 18 Norton."...it was rough, noisy, intractable...the Norton was the great racer, the man's machine, the TT hero above all others...hairy, smelly and slightly piratical...the Model 18 was the king."