Hi Jenna,
I vegetable garden in the US, in the Pacific Northwest Corner near Seattle, WA. Among other things, I grow strawberries, had a good crop this year!
Just an idea to try for your berries with the flies. The netting you speak about I assume is bird netting, but the mesh would be too large to block the flies. It?s usually has about a ½ inch opening.
Here in the States, we have what we call Crop or Floating Row Covers. Here?s a brief description of one kind that is on the market.
SUMMER INSECT BARRIER. Keep unwanted insects out. This lightweight fabric provides an effective screen to reduce damage from flea beetles, thrips, aphids, whiteflies, striped cucumber beetles and other insects that are virus vectors. Porous to both air and water. It allows 90-93% light transmission with out heat build up and is UV stabilized so it won?t deteriorate quickly.
Jenna, try your favorite garden center or nursery store. Make sure you follow directions when you place it down, so the flies can?t find a way to get under it and do their damage. Maybe spray or dust them first with a harmless to human repellant, before you cover.
Welcome to the Forum, Jenna.
Toby