Anyone with an allotment?

Yes! How long do you keep cropping and how do you care for it? We planted a few last year so this is their first productive year. They're super leggy and the flowers don't really make clumps, look more like sprouting broccoli. Read about cutting them back and also making sure to always cut the flowers off otherwise it seeds and dies? Also, absolute snail magnets, hundreds of the bastard things on each plant.