I've heard that spraying with water helps, my father used to do it.
No insects would be a problem. Maybe you could plant something near them to attract some bees, or even a potted plant with flowers

In dry climates, spraying with water weekly helps encourage predatory mites, which eat spider mites, thrips, and new hatchlings of many other pests. Most beans are self-pollinated, though small bees will produce an improved crop.

plenty of time , just keep roots watered should be getting babies halfway through August

Beans always seem to pause for breath before they start producing

I have seen on my visits to West Dean among others the Spanish Flag vine [ Ipomoea lobata ] being used as a bee attraction, growing up & through the beans

It looked fabulous but even having bought seeds I have not yet tried it

https://gardenmaking.com/salute-annual-spanish-flag-vine/

most years I grow sweet peas with the beans as they like similar conditions and that attracts the pollen beetles too. pretty flowers from the sp and beans too.

mine have only just started producing bean-lets, ready to pick in a week or so I guess.

Thanks folks.My sweet peas are a long way from the beans this year, but I'll take heart and not panic yet! I did see a bumble bee near the beans today but it looked supremely uninterested in the flowers...

I did get a set of apples once when there were no other apples near by bringing home a spray of apple flowers
and putting them in a jar beside the tree... desperate remedies but it did work. Maybe I'll put a jar
of sweet peas under the wigwam - if it works I'll let you know. But come to think of it there were no bees round the sweet peas either...