Binocular Microscope Recommendations

There are two companies I would recommend - GT Vision, and Brunel Microscopes. Both have a good reputation, and may be able to find a demonstration or used microscope at a reduced price. As a rule, you get what you pay for. The cheaper the model, the less good will the optics and lighting be. If you can visit either company, take the opportunity to try out the instrument on an actual specimen, before you make a decision.

That’s really helpful, thanks Tony. Just to confirm as well, would people be using a stereo microscope generally to look at Diptera?

Yes, a stereo microscope is the most useful tool (though a good hand lens can be really helpful). If you want to study some of the tiny species, it may be necessary to slide mount them, in which case a compound microscope makes for better viewing. 

Tony, you’re an absolute hero. Many thanks.