How to get rid of flies...

[Anthraquinone]

Why not try an old lady.
The rhyme "there was an old lady ...... " suggests it may work

 

[bradleyheathhays]

Wow lots of good ideas. Flypaper and closing the shop with screen seems to be the best bet. Although I might try putting something outside the shop to attract them away, that sounds like a good idea actually.

 

[D_W]

Wow lots of good ideas. Flypaper and closing the shop with screen seems to be the best bet. Although I might try putting something outside the shop to attract them away, that sounds like a good idea actually.

If you put something near your shop, some flies will go to it and some will go into your shop. The screen is your best bet, and a flyswatter or strip for the one or two that get in when you're opening the areas. Not sure what your dust situation is, but that would allow fine dust to escape, too.

 

[hairy]

Chatting with a rentokill rep a few years ago he saw our bug zapper in our kitchen and suggested that's not advised cos when the flies get zapped the exploding bits can carry some distance, not good near food prep.
So we swapped to a similar light in front of a sheet of bug paper in one combined not too bad to look at light. Works well, one change of sheet a year roughly, bulb change every two.

 

[Ttrees]

A big Bill Pentz cyclone would likely scare the bejaysus out of them.