#3
Jindrich Rohacek is the specialist, but to me this looks more like
Anthomyza collini/anderssoni based on the head being more elongate than in
A. gracilis.
#4
Just received confirmation from Jindrich Rohacek that it is indeed either
Anthomyza collini or
A. anderssoni. There is a high probablility (95%) that this is
A. collini.
A. anderssoni usually has a more reddish thorax and should be found in
Typha growth. But to be totally sure, examination of the terminalia is required.