Wow - very nice fly ... did you take a specimen? I can't say for sure what it is (because it is so far outside my region and I have never seen on like that) but it looks like a tachinid of the tribe Goniini. Perhaps Theo has seen it somewhere before?
It's Microphthalma europaea, a southern species indeed, relative of Dexiosoma.
Antennae are plumose, but impossible to see in this pic (that would have helped, wouldn't it, Chris ?)