Anyone found an anti-insect product that actually works?

Last couple of days/evenings in the garden when I have been trying to do a few chores, I have been tortured by flies, so much so that I had to stop what I was doing a retreat indoors:mad:

Not midges but actual flies of some description, must be the sweat attracting them. Once they try to get into your lughole they won't give up, and follow me around even when I walk quite a distance away.

So wondering if there is any product out there that will actually repel them?

Failing that, I am going to have to go with one of these:eek: