Runner bean stalks - Cut the top off?

Evening all

Out of all the runner beans I planted, most have been eating by slugs and snails. One or two have been plucked out the ground by birds, but a few are thus far surviving. One of them in fact has passed the top of its bamboo cane. Its about 6ft high. I've stuck a longer cane next to it for now, which will give up to about 7ft. Am I supposed to nip the top off to limit its height, or do I just leave it to do its thing?

 

Deffo nip the top out, I grew them last year and did'nt, they gave a good crop but were ten feet tall, this year I've taken the tops out, of mine and my mates, you can see the plant grows tons more flowers/beans, it makes them side shoot, nip the side shoots out too (when they get to the hieght of your canes.

Good Luck, PP.