Unknown fly

Unknown fly

Observation - Unknown fly. Description: I've seen this tiny fly several times during the last couple of weeks of July, always on ragwort flowers. I wondered if it might be a soldier fly, but I can't find any like it in my field guides. Any id suggestions, please.

I've seen this tiny fly several times during the last couple of weeks of July, always on ragwort flowers. I wondered if it might be a soldier fly, but I can't find any like it in my field guides. Any id suggestions, please.