Brassica watering & questions

I have cabbages, cauliflowers and calabrese which I planted in late July. So far there are lots of leaves but the cauliflowers have no curds that I can see, and the calabrese have only the odd little Curd that would eventually make up the head. They were grown from plugs and before planting, I prepared the soil by turning in GrowMore but they have had nothing but water since. According to the info on the site, they should be harvested around October time but they look no where near ready and doubt they will be ready for then.
I don’t know if I am watering them too often (they are in a raised bed which is on top of concrete so have been following the advice that containers need water every day, but I don’t drown them), or if I should be adding more GrowMore or Chicken Manure Pellets or something?

Any advice?

Thanks in advance.