I agree he does appeal to a wider audience rather than just to grumpy old timers.

I enjoy Guy Martin as well and it is interesting to compare their styles. GM presents shows, well made of course, which highlight his gung ho action man style. HC does not do that he admits openly that he is NOT an expert on motorcycles and doesn't know a ring spanner from a timing disc. he is in fact very open about his lack of mechanical skills.
So chalk and cheese but both are very entertaining.