Learn about flies

Is this Hydrotaea diabolus please? Beds alder woodland.

Hi I just want to know if I'm in the right ballpark for both before recording, both in a garden today next to a relatively unmanaged field and near Therfield Heath Herts.

I want to say Melanostoma scalere as there does seem to be a greyish frons but its a first for me and the Scaeva just seems too small and early though judging by the wing condition it may have overwintered.

Ps ok Scaeva could just be a dark Eupodes luniger with very yellow face but woud still like confirmation.

This specimen turned up in a moth trap at High Batts Nature Reserve near Ripon last week.

Might this hoverfly be Eupeodes luniger?

Might this hoverfly be a Chequered Hoverfly - Melanostoma scalare?

Might this hoverfly (same in both photographs) be Eristalis horticola?