There are mosquitoes, there are gnats (sometimes spelt Nats) and then there are midgies.
I saw the documentary and it was fascinating if somewhat full of grue ( grueful or gruesome , not sure, whatever). What I do know is that they are ' horrible wee blighters and if the conditions are right the will eat anyone alive. Sprays, garlic and Skin So Soft are all but useless. The only thing that works is a fine voile full head and face net, thick jeans ( chest waders are even better!) gloves and full arm covering. Any exposed skin will be voraciously attacked.
They will dive bomb, crawl and burrow through just about anything else. Sometimes it's best to avoid the hills between late June and the end of September.
Anyone who comes up with an effective deterrent will make a fortune, probably from me!