I haven't seen the traps, I'll look them up.
I did some searching around some kind of self-applied fly deterrents, and got a lot of US ranchers discussing hessian sacks of some sort f chemical dust, or using something involving diesel

My other problem is that our remit is based around attracting wildlife, so I can't remove the insect food source for the birds etc. I need a "bird buffet over here" sign!