These are pollen beetles which are becoming a big pest. It seems that they multiply on the oil seed rape grown in the countryside and then when the rape is over they all migrate to our gardens where they infest various flowers.
My experience most seasons is that sooner or later they will disappear from things like beans and you should still get a good later crop, even if you are losing some of the early beans.
The only other alternative is use to lots of nasty pesticides but these may kill off the natural predators like ladybirds and hover flies which will in time control the beetles anyway.

Thanks very much I will try not to get too upset each morning when I count the number of flowers eaten.

Have you tried just blasting them with a concentrated spray from a hose? That will knock them off the flowers and plants and although they'll clamber back up it should hold them back a bit.