Where are all the flies coming from?

We live in the countryside in a village. There is a thatched house next door and the flies seem to be all over it.. they are also all over everything in my garden. The fence (wooden), garage. pot plant edges steamer chairs and my outhouse roofs and obviously when I go in the garden.. me! They are little brown bodied black everything else buzzing b--g--s worse when full sunshine.. nearly everyday of the last week aaargh