Learn about flies

Hi, I’m a beginner, but have had an interest in entomology for 50 odd years - during which time I have seen a crane fly ‘taken’ by another fly. I have attached photos. Any idea what the predator is, please?

The location was long grass on a field edge. Limestone. 
Many thanks,

Max Elvidge

This ?Platycheirus female was photographed at Hiigh Batts  NR, Ripon a couple of days ago, It looks like a Platycheirus - can anyone confirm

Hello everyone - I'm new to the group.

Thank you for allowing me to join, John:)

I just wondered if there is a list (with photos if poss) of any UK diptera species that are protected?

Many thanks, Vanessa

Are there any easily available references for this family?

Are the black basicosta and T2, and the bristles on the rear edge of T3, sufficient to make this a male Luclila silvarum?

I've got a female Helina that's keying out confidently to the fratercula/consimilis/vicina couplets in the Fonseca RES key to Muscidae. It's clearly not fratercula, as the hind tibia have no posterodorsals (or scars) and it has only one anteroventral. However, the mid femur have three (slightly postero)ventral near the base, which would seem to rule out consimilis and vicina. I'm therefore at a bit of a loss.

Another one I thought might be easy... will I never learn!   This was on a knapweed in chalk grassland in Bucks on 16/6/21

Any thoughts or pointers please.

Thanks

Two flies that I think should be 'doable' from photos but I need some help please,  both were from damp nutrient poor meadows rich in Dyers Greenweed and a good range of other plants.

Any thoughts welcome