Hey You! - Yes, You Fathead.

No, not being rude.  This fly belongs to a group known as fat-headed flies.

Their larvae are internal parasites of bees / bumble bees (the bee does not survive the experience).

I am 95% sure this one is Conops quadrifasciatus.  If so, it is not often recorded here in Fifeshire, there being just 10 records on iRecord in the last 10 years.  None of them have been verified so it looks like there isn't an expert for this species.  I will add my record shortly but I don't expect any different response.

The sighting was at Silver Sands, Aberdour, Fife

I parked up in Burntisland then walked the coastal path to Aberdour where I had soup and a coffee at The Sands Cafe before returning to Burntisland by the same route.