Where have my runner beans gone

Plenty flowers on my plants but it looks as if flower "stalks/stems" have been stripped bare and I have no beans on the lower parts of the plant. Can't find any insects etc. Well watered and fed.Any ideas please

It's not unusual for the early bean flowers to fail to set, particularly if it is either too hot or too windy! ( )

I have known sparrows to peck the ends out of the flowers but luckily it doesn't seem to be a habit they have all got into!

The result is the same; bare flower stalks.

Things should get better when the weather calms down a bit, although it's a lot of work for just the bumble bees and other insect pollinators as I've hardly seen any honey bees round here this year. 

Thanks JayG, garden south facing so has been very hot and now very windy,haven't seen slugs or snails, plants are in veg bag and growing up the inside of my rose arch.

I'm sure this has been mentioned before on here - but there are more than one type of bee and some will bury themselves into the back of the flower and stop it forming a bean. Later in the year, hopefully now, the more beneficial bee will pollinate the flowers and beans should start coming.

GLUT? 
No such thing as a glut of runners IMO