Hi Richard, I'm also in the same boat. I searched for week then came across this place in Israel (https://www.ebay.com/itm/173057626714), ordered mine and waiting for delivery. I also spoke to a guy in Australia who I saw have it on his bike and he says it works for about an hour's ride. (https://www.facebook.com/groups/1814560972150056/permalink/2071534199786064/) I'm then also looking for a sheepskin, which I saw some at Dischem, but they don't sell black ones. Apparently the AirHawk is also not that effective, some guys swear by it and others not - as with all things we buy.
Let me know what you decide on and please share :-)