I made my own fly screen for our Kampa hayling 6 air tent as it doesn't have a fly sheet on the main door. And like many other they drive me crazy.. I hate them lol.. I brought the fly screen doors,the ones that you put on your own front or back door at home from b&ms £3.99 x 2 I used three panels, sewn 2 panels together and sewn across the top to keep them attached.. kept the magnate catches in the middle to walk in and out of, put some toggles on the side to attach to the little hoops in the tent near the windows.. and it works okay. Okay still get an odd fly cause the wind blows it a bit but no way near as many as normal. Hope it works for you 😀
In Kent we seem to be having a plague of green blue bottle flies. They come in through open windows and buzz about until introduced to French fly and mozzie spray.
I had a mozzie problem in my tent in Northern France a few years ago.