Dart Fly-screens

I've seen a few previous posts regarding Dart Fly-screen's & a couple of months ago I saw a bike which was being serviced at the factory with one fitted. This was a standard screen attached to the bike via the headlamp bolts. I have subsequently contacted Dart directly and pointed out that the Commando headlight brackets incorporate cast in fixings, which are used for the Norton Carbon Fibre fly-screen. The cost of a Dart screen is significantly less than the factory version (£90 versus £250) and available in two sizes, both of which I think would provide greater wind protection. Steve, who owns Dart has stated that he would need to sell approximately 100 units to make the design and manufacture effort worthwhile. Do people think that there are sufficient bikes out there to warrant the investment?