If the Blackfly are on your Runner Beans try growing a Lemon Balm Plant in a large pot. Sink the pot in the ground by the row next year. This worked well for 2 years for me. No Blackfly at all, so the birds didnt knock my Runner Bean flowers off when aiming for the insects. I had a crop on July 24th, even with this awful weather we have had. Have transplanted it now into a polystyrene caterers box, as it tends to spread like a weed. It can stay there, as Runner Beans can be grown in the same place year after year without crop rotation.

You can buy an organic Garlic Barrier spray,Brymac..very effective,and suitable to use on foodie plants..or any others in your garden..you can also make your own,by steeping a Garlic bulb in water,and diluting it for use in a spray....

I turn the hose pipe on them and/or spray with soapy water with a drop of cooking oil in it.

I used to spray late evenings with one teaspoon Dettol in a pint of water. The birds dont like the smell of this and leave the flowers alone. The Dettol attracts the Bees which pollinate the flowers.
Since I planted the Lemon Balm Plant I havent needed to even do this.

thanks for all your answers , i will try them and let everyone know how i get on thanks once again brymac