I think the secret is to keep your land clean. Strim like crazy and keep the grass and weeds at bay. You should see a big difference.

Also, we were over last week and took some American Pitcher Plants with us and within a few minutes of them being out on the patio area you should have seen the flies crowding round them. Great investment, then just place them around the patio or close to the house and hope that they get attract the flies before they get to you.

If you don't know they are long trumpet shaped and in the sun they turn red on the ends and produce a sticky appetising glue type substance that the flies are attracted to and when they land on the plant and get encouraged to travel down inside the trumpets the plant has the little buggers in it's grip as inside there are tiny hairs pointing downwards and the flies cannot escape,  and we get fat plants........