This is a 1936 Norton brochure (contributed by Wim); too large to reproduce properly on a Blog page but the introduction (copied below) says it all:
"Here are a few letters of appreciation that we have recently received. We did not ask for them - they were sent spontaneously - obviously as the result of the enthusiasm aroused by the splendid performance of the "Unapproachable" NORTON. As you read these letters it must be perfectly clear that only a machine quite out of the ordinary could provoke such genuine approval."
This photo from the brochure shows Jimmy Guthrie on what appears to be a trials version of the M30 International. Fitting an obsolete acetylene lighting kit must have been less work than fitting a magdyno!