They are not being pollinated so are being visited by less insects this year. Have you noticed a lack of insects in the garden this year, Macpat, or are the beans in a different position to usual? It might be worth going round the rest of the flowers with a feather or small paintbrush and doing the business yourself.

Thank you Bulbaholic. They are actually in a different position this year as last year they were affected by strong winds. They get sun from about 11 am until it sets. There have been loads of insects, especially Bees. I cannot move the container now as it is too heavy so will try the paint brush method.