I know you UK guys have to pay a lot for this stuff, BUT...
If it works just as advertised...
I can't help but think for that kind of money you could get a 180V PM DC 1/2HP 1750RPM shipped in from the US, add some VAWT blades, and beat the tar out of those output numbers, for a LOT less money.
Gosh. $750 for 10W at Force 8 / 40MPH?
Force 9 wind causes 'Light structure damage'.
Force 4 / 13-18MPH looks like only 3W, which is easy to beat with a (non-VAWT) box fan blade and stray parts in a Force 3 wind.
Force 3 / 8-12MPH looks like only 135ma.
Even if it sells for 1/4-price... Wow.
G-