Confidence: It might be this.
Notes: I can't say much about this as I don't know the Muscidae too well myself, but I'd think there's a good chance it might be a Phaonia or Helina species. But please regard this as speculation! Many of these are fair-sized flies, about the size of a house fly (Musca). The food of the larvae is diverse, but includes fungi, dung and rotting vegetation. As far as I'm aware none are vectors of disease.