Mark Sturtevant wrote:
They are snipe flies (Rhagionidae). There are a couple with similar markings, but I can't find one with the black shiny spots on the head. So unless there is a British equivilant of BG, this might not get much further.
Thanks Mark, I found another today in the local park. I will search Snipe flies now, it is the first I have seen of its kind.