I think this is a bloody good move from Ewan & Charley, their production team and especially Harley Davidson.
We all know that Harley Davidson is in deep trouble for the simple reason that their average age of buyer is just under 100.
I think HD has also missed the bus a little, compared to BMW back in Long Way Round times.
When that aired, no one had ever heard of Charlie, but Ewan was still fresh in everyone's minds from Moulin Rouge, Star Wars I & II, The Island, Trainspotting wasn't that long ago. All the coming of age youngsters where inspired - I was one of them, went out and bought an F650GS. (All I could afford on a starting out salary)
Now years later, the only people who have heard of Charlie are people who watched long Way Round/Down, and Ewan is no longer a name youngsters know.
The people who will watch the first trips have already bought their 1200GSs, and anyone who didn't see previous trips, and who still is vaguely interested in Ewan (or Charlie) will be close to 100, so the average age of Harley buyers not likely to drop too much.