Flies aren’t supposed to be about in witner but we returned home to find a couple of dozen of live ones and a similar number of their dead relatives in the bedroom, which is the sunniest room in the house.
I think they’re cluster flies. The larvae of the species feed on earthworms in lawns and pastures over summer and in autumn the adults move inside.
I’m not keen on flies in general and dislike these in particular because they’re very difficult to get rid of.
One of the unpleasant features is their ability to store fat which causes vacuum cleaner bags to rot if you leave the flies in them.